#85 Average Quantitative Aptitude Question

In Arun's opinion, his weight is greater than 65 kg but leas than 72 kg. His brother does not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all of them are correct in their estimation, what is the average of diferent probable weights of Arun ?

A) 55.5 kg
B) 66.5 kg
C) 77.5 kg
D) 88.5 kg

Answer: B) 66.5 kg 

Explanation:

Let Arun's weight be X kg.

According to Arun, 65 < X < 72.

According to Arun's brother, 60 < X < 70.

According to Arun's mother, X < 68.

The values satisfying all the above conditions are 66 and 67.

Required average = (66 + 67) / 2 = 66.5 kg

#83 Average Quantitative Aptitude Question

The average of 7 consecutive numbers is 20. The largest of these numbers is :

A) 21
B) 22
C) 23
D) 24

Answer: C) 23 

Explanation:

Let the numbers be x, x + 1, x + 2,  x + 3, x + 4, x + 5 and x + 6,

Then   (x + (x + 1) + (x + 2) + (x + 3) + (x + 4) + (x + 5) + (x + 6)) / 7 = 20.

or  7x + 21 = 140 or 7x = 119 or x =17.

Latest number = x + 6 = 23.

#81 Average Quantitative Aptitude Question

The average temperature of the town in the first four days of a month was 58 degrees. The average for the second, third, fourth and fifth days was 60 degrees. If the temperatures of the first and fifth days were in the ratio 7 : 8, then what is the temperature on the fifth day ?

A) 62 degrees
B) 64 degrees
C) 65 degrees
D) 66 degrees

Answer: B) 64 degrees 

Explanation:

Sum of temperatures on 1st, 2nd, 3rd and 4th days = (58 * 4) = 232 degrees ... (1)

Sum of temperatures on 2nd, 3rd, 4th and 5th days - (60 * 4) = 240 degrees  ....(2)

Subtracting (1) From (2), we get :

Temp, on 5th day  - Temp on 1st day  = 8 degrees.

Let the temperatures on 1st and 5th days be 7x and 8x degrees respectively.

Then, 8x - 7x = 8 or x = 8.

Temperature on the 5th day = 8x = 64 degrees.

#80 Average Quantitative Aptitude Question

Of the four numbers, whose average is 60, the first is one-fourth of the sum of the last three. The first number is :

A) 17
B) 29
C) 36
D) 48

Answer: D) 48 

Explanation:

Let the first number be x,

Then, sum of the four numbers = x + 4x = 5x.

so,  5x/4 = 60 or x = (60 * 4) / 5 = 48.

#79 Average Quantitative Aptitude Question

In a class of 78 students 41 are taking French, 22 are taking German. Of the students taking French or German, 9 are taking both courses. How many students are not enrolled in either course?

A) 6
B) 12
C) 24
D) 18

Answer: C) 24 

Explanation:

You could solve this by drawing a Venn diagram. A simpler way is to realize that you can subtract the number of students taking both languages from the numbers taking French to find the number taking only French. Likewise find those taking only German. Then we have:Total = only French + only German + both + neither

78 = (41-9) + (22-9) + 9 + neither.

Not enrolled students = 24

#77 Average Quantitative Aptitude Question

David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, Mathematics,Physics, Chemistry and Biology What are his average marks ?

A) 75
B) 68
C) 65
D) 60

Answer: A) 75 

Explanation:

Average =   (76 + 65 + 82 + 67 + 85 )/ 5 = 375/5   =  75.

#76 Average Quantitative Aptitude Question

If the mean of a, b, c is M and ab + bc + ca = 0, then the mean of  is :

A) MB) 3 M^2C) 2 (M/3)D) M^2

Answer: B) 3 M^2 

Explanation:

We have : ( a + b + c) / 3 = M   or (a + b + c) = 3M.

Now.  .

     

Required mean == = .

#75 Average Quantitative Aptitude Question

The average salary of all the workers in a workshop is Rs. 8000. The average salary of 7 technicians is Rs. 12000 and the average salary of the rest is Rs. 6000. The total number of workers in the workshop is :

A) 20
B) 21
C) 23
D) 24

Answer: B) 21 

Explanation:

 Lot the total number of workers be v Then,

8OOOv = (12000 * 7) + 6000 (v - 7) <=>  2000v = 42000  <=>  v = 21.

#74 Average Quantitative Aptitude Question

The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is 

A. 45 kg
B. 50 kg
C. 53 kg
D. 55 kg

Ans: A.Sol.
Weight of the teacher
= (35.4 × 25 – 35 × 24)kg
= 45 kg.

#72 Average Quantitative Aptitude Question

In a village the average age of n people is 42 years. But after the verification it was found that the age of a person had been  considered 20 years less than the actual age, so the new average, after the correction,increased by 1. The value of n is :

A) 21
B) 20
C) 22
D) None of these

Answer: B) 20 

Explanation:

It is the same as a person with 20 years more age  replaces an existing person of the group ( or village)

Since the total age of the village having n persons, is being increased by 20 years and the average age of village is being increased by 1 year, hence there are total 20 people in the village.

 

Alternatively :  ( n x 42 ) + 20 = ( n x 43 )

                          => n=20

#71 Average Quantitative Aptitude Question

The average of the two-digit numbers, which remain the same when the dibits inter-change their positions, is :

A) 53
B) 54
C) 55
D) 56

Answer: C) 55 

Explanation:

Average = (11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 + 99) / 9

             =( (11 + 99) + (22 + 88) + (33 + 77) + (44 + 66) + 55) / 9

             = (4 * 110 + 55)/9 =  495 / 9 = 55. 

#70 Average Quantitative Aptitude Question

A cicketer bas a certain average for 10 innings, In the eleventh inning, he scorod 108 runs, thereby increasing his average by 6 runs. His new average is :

A) 44 runs
B) 46 runs
C) 48 runs
D) 49 runs

Answer: C) 48 runs 

Explanation:

Let average for 10 innings be x. Then,

(10x + 108)/11 = x + 6 => 11x + 66 = 10x + 108  =>  x = 42.

New average = (x + 6) = 48 runs.

#69 Average Quantitative Aptitude Question

The average expenditure of the hotel when there are 10 guests is Rs. 60 per guests and the average expenditure is Rs.40 when there are 20 Guests. If it is known that there are some fixed expenses irrespective of the number of guests then the average expenditure per guest  whe there are 40 guests in the hotel.

A) Rs. 30
B) Rs. 25
C) Rs. 20
D) can't be determined

Answer: A) Rs. 30 

Explanation:

Let the fixed expenditure of the hotel be Rs.x and the variable expenditure ( which is dependent on the guest ) is Rs.y , then

                   x + 10y = 600        ---------(1)

                   x + 20y = 800       ----------(2)

              10y = 200

           y = Rs. 20   and    x= 400

Hence the total expenditure when there are 40 guests = 400 + 40 x 20 = 1200

 average expenditure =  = Rs. 30

 

#68 Average Quantitative Aptitude Question

The average of 9 results is 50. The average of first four results is 52 and average of last four results is 49 . what is the fifth result?

 Answer :

Total of results = 50 x 9 = 450

Total of first four results = 52 x 4 = 208

Total of Last four results = 49 x 4 = 196

Hence the fifth result = 450 - (208 + 196) = 46

#66 Average Quantitative Aptitude Question

8 years ago there were 5 members in the Arthur's family and then the average age of the family  was 36 years. Mean while Arthur got married and gave birth to a child. Still the average age of his family is same now. What is the age of his wife at the time of his child's birth was.If the difference between the age of her  child and herself was 26 years.

A) 25 years
B) 26 years
C) 20 years
D) can't be determined

 Answer: B) 26 years 

Explanation:

Since we know that the difference b/w the age of any two persons remains always constant, while the ratio of their ages gets changed as the time changes.

so, if the age of his child be x (presently)

Then the age of  wife be x + 26 (presently)

Thus the total age = x + ( x + 26) = 32  [ 252-220 =32]

 x = 3

 The age of her child is 3 years and her self  is 29 years. Hence her age at the time of the birth of her child was 26 years.

#65 Average Quantitative Aptitude Question

The average monthly salary of the employees of a firm is Rs.60 out of the employees 12 officers get an average of Rs.400 per month and the rest an average of Rs. 56 per month , Find the number of emp

 Answer:

Actual average salary of 12 officers = 400

 Total salary of 12 officers = 400 x 12 = 4800

Average of these 12  officers as a whole =60

Total salary of 12 officers as a whole = 60 x 12 = 720

The total salary of rest  = 4800 - 720 = 4080

Difference in average of the rest of officers  = 60 - 56 = 4

Rest of the officers = 

Total number of employees = 1020 + 12 = 1032

#64 Average Quantitative Aptitude Question

123 typists typeed 984 papers in 1/15 hour. The number of papers typed for  minute by a average typist is:

A) 1B) 2C) 3D) 5

Answer: B) 2 

Explanation:

Use unitary method:

In  hours, 123 typists can type 984 paper

In 1 minute, 123 typists can type   = 246 papers

In 1 minute, 1 typist can type  =2 papers      [ Hint  hours = 4 minutes]

#62 Average Quantitative Aptitude Question

Amithab's average expenditure for the January to June is Rs. 4200 and he spends Rs.1200 in January and Rs.1500 in july.The average expenditure for the months of febraury to July is:

A) Rs. 4250B) Rs. 4520C) Rs. 4060D) None of these

Answer: A) Rs. 4250 

Explanation:

Amithab's total expenditure for Jan - June  = 4200 x 6 = 25200

Expenditure for Feb - June = 25200-1200 = 24000

Expenditure for the months of Feb - July = 24000 + 1500 =25500

The average expenditure = 

 

#61 Average Quantitative Aptitude Question

A man covers a journey from Meerut to Delhi by a car at an average speed of 40 km/hr. He returns back by scooter with an average speed 24 km/hr. Find his average speed during the whole journey?

 Answer:

Average speed =  km/hr

                      =   km/hr

#60 Average Quantitative Aptitude Question

The average of 26,29,n,35 and 43 lies between 25 and 35. If n is always an integer and greater than the average  of the given integers then the value of n is :

A) 33
B) 34
C) 33
D) None of these

Answer: C) 33
Explanation:

Average of 26,29,35 and 43 is 33.25 . Also the average of 26 , 29, n, 35 and 43 lies between 25 and 35 i.e,

 125 < 26+29+n+35+43 < 175

 125 < 133 + n < 175

  n < 42

Since the value of n is an integer and greater than 33.25 then 33 < n < 42 for every integer n.

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#58 Average Quantitative Aptitude Question

The average age of the mother and her six children is 12 years which is reduced by 5 years if the age of the mother is excluded. How old is the mother? 

A. 40 years
B. 42 years
C. 48 years
D. 50 years

Ans: B.Sol.
Therefore age of the mother
= ( 12 × 7 – 7 × 6)
= 42 years.

 

#57 Average Quantitative Aptitude Question

In an examination, a pupil’s average marks were 63 per paper. If he had obtained 20 more marks for his Geography paper and 2 more marks for his History paper, his average per paper would have been 65. How many papers were there in the examination? 

A. 8
B. 10
C. 11
D. 12

Ans: C.Sol.
Let the numbers of papers be x.
Then, 63x + 20 + 2 = 65x (or) 
2x = 22 (or) 
x = 11.

 

#55 Average Quantitative Aptitude Question

The average age of 15 students of a class is 15 years. Out of these, the average age of 5 students is 14 years and that of the other 9 students is 16 years, The age of the 15th student is :

A) 11
B) 12
C) 13
D) 14

Answer: A) 11 

Explanation:

Age of the 15th student = [15 * 15 - (14 * 5 + 16 * 9)] = (225-214) = 11 years.

#54 Average Quantitative Aptitude Question

The average age of 36 students in a group is 14 years. When teacher's age is included to it, the average increases by one. What is the teacher's age in years ?

A) 35 years
B) 45 years
C) 51 years
D) 54 years

Answer: C) 51 years 

Explanation:

Age of the teacher = (37 * 15 - 36 * 14) years = 51 years.

#53 Average Quantitative Aptitude Question

The mean temperature of Monday to Wednesday was 37C and of Tuesday to Thursday was 34C . If the temperature on Thursday was (4/5) th that of Monday, the temperature on Thursday was?

 Answer

   -----------(1)

                --------------(2)

(1) - (2) gives

 th of temperature on Monday = 

 Temperature on Monday = 

 Temperature on Thursday = 

#51 Average Quantitative Aptitude Question

The average monthly salary of 20 employees in an organisation is Rs. 1500. If the manager's salary is added, then the average salary increases by Rs. 100. What is the manager's monthly salary ?

A) 3600
B) 3700
C) 3800
D) 3900

Answer: A) 3600 

Explanation:

Manager's monthly salary Rs. (1600 * 21 - 1500 * 20) = Rs. 3600.

#50 Average Quantitative Aptitude Question

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is

A) 30
B) 40
C) 50
D) 60

Answer: B) 40 

Explanation:

Sum of the present ages of husband, wife and child = (27 x 3 + 3 x 3) years = 90 years.

Sum of the present ages of wife and child (20 x 2 + 5 x 2) years  = 50 years.

Husband's present age = (90 - 50) years = 40 years.

#49 Average Quantitative Aptitude Question

The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is :

A) 35
B) 36.5
C) 40
D) 42

Answer: B) 36.5 

Explanation:

Correct Sum = (36 * 50 + 48 - 23) = 1825.

Correct mean = = 1825/50 = 36.5

#48 Average Quantitative Aptitude Question

The average price of 10 books is Rs. 12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what ia the pice of each of these two books ?

A) 16,12
B) 10,16
C) 23,9
D) 8,7

Answer: B) 10,16 

Explanation:

Total pice of the two books = Rs. [(12 x 10) - (11.75 x 8)]

    = Rs. (120 - 94) = Rs. 26.

let the price of one book be Rs. x

Then, the price of other book = Rs. (x + 60% of x) = Rs. = Rs. 

So,  

The prices of the two books are Rs. 10 and Rs. 16

#46 Average Quantitative Aptitude Question

The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is 

A. 35.2
B. 36.1
C. 36.5
D. 39.1

Ans: C.Sol.
Therefore correct sum 
= ( 36 × 50 + 48 – 23)
= 1825.
Therefore correct mean
= 1825 / 50
= 36.5.

#45 Average Quantitative Aptitude Question

The average runs of a cricket player of 10 innings was 32. How many runs must he makes ih his next innings so as to increase his average of runs by 4? 

A. 2
B. 4
C. 70
D. 76

Ans: D.Sol.
Average after 11 innings = 36.
Therefore required numbert of runs 
= (36 × 11) – (32 × 10)
= 396 - 320
= 76.

 

#43 Average Quantitative Aptitude Question

The average age of 36 students in a group is 14 years. When teacher’s age is included to it, the average increases by one. What is the teacher’s age in years? 

A. 31
B. 36
C. 41
D. 51

Ans: D.Sol.
Age of the teacher = ( 37 × 15 – 36 × 14 ) years = 51 years.

 

 

#42 Average Quantitative Aptitude Question

Three years ago, the average age of A and B was 18 years. With C joining them, the average age becomes 22 years. How old is C now? 

A. 20 years
B. 24 years
C. 27 years
D. 30 years

Ans: B.Sol.
Present age of ( A + B) = ( 18 × 2 + 3 × 2) years = 42 years.
Present age of ( A + B + C) = (22 × 3) years = 66 years.
Therefore C’s age = (66 – 42) years
= 24 years.

 

#40 Average Quantitative Aptitude Question

In a school with 600 students, the average age of the boys is 12 years and that of the girls is 11 years. If the average age of the school is 11 years 9 months, then the number of girls in the school is 

A. 150
B. 200
C. 250
D. 350

Ans: A.Sol.
Let the number of grils be x.
Then, number of boys = (600 - x).
Then, (11 3/4 × 600)
⇔ 11x + 12(600 - x) ⇔ x = 7200 - 7050 ⇔ 150.

 

#39 Average Quantitative Aptitude Question

In Prasanna's opinion, his weight is greater than 65 kg but less than 72 kg. His brother does not agree with Prasanna and he thinks that Prasanna's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all of them are correct in their estimation, what is the average of different probable weights of Prasanna? 

A. 67 kg
B. 68 kg
C. 66.5 kg
D. 69 kg

Ans: C.Sol.
Let Prasanna's weight be X kg.
According to Prasanna, 65 < X < 72.
According to Prasanna's brother, 60 < X < 70.
According to Prasanna's mother, X < 68.
The value satisfying all the above conditions are 66 and 67.
∴ Required average = [ 66 + 67 / 2 ] = [133 / 2] = 66.5 kg.

 

#37 Average Quantitative Aptitude Question

The average age of a group of persons going for picnic is 16 years. Twenty new persons with an average age of 15 years join the group on the spot due to which their average age becomes 15.5 years. The number of persons initially going for picnic is :

A) 15
B) 20
C) 23
D) 24

Answer: B) 20 

Explanation:

Let the initial number of persons be x. Then,

16x + 20 * 15 = 15.5 (x + 20) <=> 0.5x = 10 <=> x = 20.

#36 Average Quantitative Aptitude Question

The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is :

A) 25
B) 35
C) 45
D) 55

Answer: B) 35 

Explanation:

Excluded number = (27 x 5)  -  (25 x 4) = 135 - 100 = 35.

#35 Average Quantitative Aptitude Question

In an NGO the daily average wages of 20 illiterate employees is decreased from Rs.25 to Rs.10, thus the average salary of  all the literate and illiterate  employees is decreased Rs.10 per day. The No. of educated employees working in the NGO is :

A) 15
B) 20
C) 10
D) Data Insufficient

Answer: C) 10 

Explanation:

Total employees = 

Hence number of educated employees  = 30-20 = 10

#34 Average Quantitative Aptitude Question

A family consists of grandparents, parents and three grandchildren. The average age of the grandparents is 67 years, that of the parents is 35 years and that of the grandchildren is 6 years. What is the average age of the family ?

A) 31( 5/7)
B) 32 (6/7)
C) 34(4/7)
D) 35(4/9)

Answer: A) 31( 5/7) 

Explanation:
Required average = (67 * 2 + 35 * 2 + 6 * 3) / (2 + 2 + 3)

 = (134 + 70 + 18) / 7  =  222 / 7 = 31(5/7) years.

#32 Average Quantitative Aptitude Question

The average salary of all the workers in a workshop is Rs. 8000. The average salary of 7 technicians is Rs. 12000 and the average salary of the rest is Rs. 6000. The total number of workers in the workshop is 

A. 20
B. 21
C. 22
D. 23

Ans: B.Sol.
Let the total number of workers be x. Then,
8000x = (12000 × 7) + 6000 ( x – 7)
‹=› 2000x = 42000
‹=› x = 21.

#30 Average Quantitative Aptitude Question

If the arithmetic mean of seventy five numbers is calculated, it is 35. If each number is increased by 5, then mean of new numbers is 

A. 30
B. 35
C. 40
D. 50

Ans: C.Sol.
A.M. of 75 numbers = 35.
Sum of 75 numbers = (75 x 35) = 2625.
Total increase = (75x5) = 375.
Increased sum = (2625 + 375) = 3000.
Increased average = 3000 / 75 = 40.

#29 Average Quantitative Aptitude Question

The average of 11 results is 60. If the average of first six results is 58 and that of the last six is 63, find the sixth result. 

A. 22
B. 44
C. 66
D. 72

Ans: C.Sol.
Sixth result = (58 x 6 + 63 x 6 - 60 x 11) = 66.

#27 Average Quantitative Aptitude Question

The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% of a mean score of 31. The mean score of remaining 55% is 

A. 40.8 approx
B. 45.3 approx
C. 51.4 approx
D. 53.8 approx

Ans: C.Sol.
Let the required mean score be x. Then,
20 × 80 + 25 × 31 + 55 × x = 52 × 100
⇔ 1600 + 775 + 55x = 5200
⇔ 55x = 2825
⇔ x = 565 / 11 = 51.4.

#26 Average Quantitative Aptitude Question

A library has an average of 510 visitors on Sunday and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is 

A. 258
B. 276
C. 280
D. 285

Ans: D.Sol.
Since the month begins with a Sunday, so there will be five Sundays in the month.
∴ Required average = [510 x 5 + 240 x 25 / 30] = 8550 / 30 = 285.

#23 Average Quantitative Aptitude Question

Find the average of all prime numbers between 30 and 50. 

A. 30
B. 33.6
C. 39.8
D. 44.9

Ans: C.Sol.
There are five prime numbers between 30 and 50.
They are 31, 37, 41, 43 and 47
∴ Required average = [31 + 37 + 41 + 43 + 47 / 5] = 199/ 5 = 39.8.

 

 

#21 Average Quantitative Aptitude Question

The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% of a mean score of 31. The mean score of remaining 55% is 

A. 40.8 approx
B. 45.3 approx
C. 51.4 approx
D. 53.8 approx

Ans: C.Sol.
Let the required mean score be x. Then,
20 × 80 + 25 × 31 + 55 × x = 52 × 100
⇔ 1600 + 775 + 55x = 5200
⇔ 55x = 2825
⇔ x = 565 / 11 = 51.4.

#24 Average Quantitative Aptitude Question

The captain of a cricket team of 11 members is 26 years old and the wicket keeper is 3 years older. If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team. What is the average age of the team? 

A. 23 years
B. 24 years
C. 25 years
D. 27 years

Ans: A.Sol.
Let the average age of the x whole team be x years.
∴ 11x - (26 + 29) = 9( x - 1 ) 
⇒ 11x - 9x = 46
⇒ 2x = 46 
⇒ x = 23.
So, average age of the team is 23 years.

 

#20 Average Quantitative Aptitude Question

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is 

A. 35 years
B. 40 years
C. 50 years
D. 60 years

Ans: B.Sol.
Sum of the present ages of husband, wife and child 
= (27x3+3x3) years = 90 years.
Sum of the present ages of wife and the child 
= (20 x 2 + 5 x 2) years = 50 years.
∴ Husband's present age = (90 - 50) = 40 years.

#19 Average Quantitative Aptitude Question

The average weight of 10 oarsmen in a boat is increased by 1.8 kg when one of the crew, who weighs 53kg is replaced by a new man. find the weight of the new man. 

Sol. Total weight increased = (1.8 * 10)kg = 18kg.
∴ Weight of the new man = (53 + 18)kg = 71kg.

#17 Average Quantitative Aptitude Question

Find the average of first 20 multiples of 7. 

Sol. Required average = 7(1+2+3 ... + 20) / 20 = [7 * 20 * 21 / 20 * 2] = [147 / 2] = 73.5.

#16 Average Quantitative Aptitude Question

Find the average of first 40 natural numbers. 

Sol. Sum of first n natural numbers = 40 * 41 / 2 = 820.
∴ Required average = 820 / 40 = 20.5.

#15 Average Quantitative Aptitude Question

Find the average of all prime numbers between 30 and 50. 

Sol. There are five prime numbers between 30 and 50.
They are 31, 37, 41, 43 and 47.
∴ Required average = [(31 + 37 + 41 + 43 + 47) / 5] = 199/5 = 39.8.

#13 Average Quantitative Aptitude Question

Average of 10 numbers is zero. At most how many numbers may be greater than zero

A. 0
B. 1
C. 5
D. 9

 Answer And Explanation

Answer: Option D

#12 Average Quantitative Aptitude Question

The average of four consecutive odd numbers is 24. Find the largest number.

A. 25
B. 27
C. 29
D. 31

 Answer And Explanation

Answer: Option B

Explanation:

Let the numbers are x, x+2, x+4, x+6, then 

=>x+(x+2)+(x+4)+(x+6)4=24=>x+(x+2)+(x+4)+(x+6)4=24

=>4x+12)4=24=>4x+12)4=24

=>x+3=24=>x=21=>x+3=24=>x=21

So largest number is 21 + 6 = 27

 

#11 Average Quantitative Aptitude Question

Find the average of first 10 multiples of 7

A. 35.5
B. 37.5
C. 38.5
D. 40.5

 Answer And Explanation

Answer: Option C

Explanation:

=7(1+2+3+...+10)10=7(1+2+3+...+10)10

=7(10(10+1))10×2=7(10(10+1))10×2

=7(110)10×2=38.5=7(110)10×2=38.5

#10 Average Quantitative Aptitude Question

Find the sum of first 30 natural numbers

A. 470
B. 468
C. 465
D. 463

 Answer And Explanation

Answer: Option C

Explanation:

Sum of n natural numbers

=n(n+1)2=n(n+1)2

=30(30+1)2=30(31)2=465=30(30+1)2=30(31)2=465

#9 Average Quantitative Aptitude Question

Reeya obtained 65, 67, 76, 82 and 85 out of 100 in different subjects, What will be the average.

A. 70
B. 75
C. 80
D. 85

 Answer And Explanation

Answer: Option B

Explanation:

(65+67+76+82+855)/75(65+67+76+82+855)=75

 

#8 Average Quantitative Aptitude Question

Average of all prime numbers between 30 to 50

A. 37
B. 37.8
C. 39
D. 39.8

 Answer And Explanation

Answer: Option D

Explanation:

Prime numbers between 30 and 50 are:
31, 37, 41, 43, 47

Average of prime numbers between 30 to 50 will be

(31+37+41+43+475)=1995=39.8(31+37+41+43+475)=1995=39.8

 

#7 Average Quantitative Aptitude Question

A motorist travel to a place 150 km away at an avearge speed of 50 km/hr and returns ar 30 km/hr.His average speed for the whole jouney in km/hr is

A. 36.5 km/hr
B. 37.5 km/hr
C. 35.5 km/hr
D. 34.5 km/hr

Answer: Option B

Explanation:

Average speed will be 

2xyx+ykm/hr2xyx+ykm/hr

= \frac{2(50)(30)}{50+30} km/hr
= 37.5 km/hr

#5 Average Quantitative Aptitude Question

The average of six numbers is X and the average of three of these is Y.If the average of the remaining three is z, then

A. x = y + z
B. 2x = y + z
C. x = 2y + z
D. x = y + 2z

Answer: Option B

Explanation:

X =((3y+3z)/6)
or
2X= y + z

#14 Average Quantitative Aptitude Question

Find the average of all numbers between 6 and 34 which are divisible by 5

A. 15
B. 20
C. 25
D. 30

 Answer And Explanation

Answer: Option B

#4 Average Quantitative Aptitude Question

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is

A. 40
B. 35
C. 45
D. 55

Answer: Option A

Explanation:

Sum of the present ages of husband, wife and child = (27 * 3 + 3 * 3) years = 90 years.

Sum of the present ages of wife and child = (20 * 2 + 5 * 2) years = 50 years.

Husband's present age = (90 - 50) years = 40 years

#3 Average Quantitative Aptitude Question

If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is

A. 54.48
B. 54.68
C. 54.60
D. 54.58

Answer: Option B

Explanation:

(55×50)+(60×55)+(45×60)55+60+45(55×50)+(60×55)+(45×60)55+60+45

8750160=54.688750160=54.68

#2 Average Quantitative Aptitude Question

The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is

A. 45
B. 50
C. 55
D. 60

Answer: Option A

#1 Average Quantitative Aptitude Question

Average of 10 matches is 32, How many runs one should should score to increase his average by 4 runs.

A. 70
B. 76
C. 78
D. 80

Answer: Option B

Explanation:

Average after 11 innings should be 36

So, Required score = (11 * 36) - (10 * 32)
= 396 - 320 = 76

#22 Average Quantitative Aptitude Question

If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is 

A. 53.33
B. 54.68
C. 55
D. 57

Ans: B.Sol.
Required average = [55x50 + 60x55 + 45x60 / 55 + 60 + 45]
= [2750 + 3300 + 2700 / 160]
= 8750 / 160 = 54.68.

#25 Average Quantitative Aptitude Question

A library has an average of 510 visitors on Sunday and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is 

A. 250
B. 276
C. 280
D. 285

Ans: D.Sol.
Since the month begins with a Sunday, so there will be five Sundays in the month.
∴ Required average = [510 x 5 + 240 x 25 / 30] = 8550 / 30 = 285.

#28 Average Quantitative Aptitude Question

Find the average of all prime numbers between 30 and 50. 

A. 30
B. 33.6
C. 39.8
D. 44.9

Ans: C.Sol.
There are five prime numbers between 30 and 50.
They are 31, 37, 41, 43 and 47
∴ Required average = [31 + 37 + 41 + 43 + 47 / 5] = 199/ 5 = 39.8.

 

 

#31 Average Quantitative Aptitude Question

A company produces on an average 4000 items per month for the first 3 months. How many items it must produce on an average per month over the next 9 months, to average of 4375 items per month over the whole? 

A. 4500
B. 4600
C. 4680
D. 4710

Ans: A.Sol.
Required average = (4375 x 12) - (4000 x 3 ) / 9 
⇔ 52500 - 12000 / 9 
⇔ 40500 / 9
= 4500.

#41 Average Quantitative Aptitude Question

In the first 10 overs of a cricket game, the run rate was only 3.2. What should be the run rate in the remaining 40 overs to reach the target of 282 runs? 

A. 6.25
B. 6.5
C. 6.75
D. 7

Ans: A.Sol.
Required run rate = 282 - (3.2 x 10) / 40 = 250/40 = 6.25.

#87 Average Quantitative Aptitude Question

The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What might be the weight of the new person? 

A. 76 kg
B. 76.5 kg
C. 85 kg
D. 90 kg

Ans: C.Sol.
Total weight increased 
= (8 × 2.5) kg
= 20 kg.
Weight of new person 
= (65 + 20) kg
= 85 kg.

#47 Average Quantitative Aptitude Question

The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero? 

A. 0
B. 1
C. 10
D. 19

Ans: D.Sol.
Average of 20 numbers = 0.
Therefore sum of 20 numbers = (0 × 20 ) = 0.
It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (- a).

#33 Average Quantitative Aptitude Question

In the first 10 overs of a cricket game, the run rate was only 3.2. What should be the run rate in the remaining 40 0vers to reach the target of 282 runs? 

A. 6.25
B. 6.5
C. 6.75
D. 7

Ans: A.Sol.
Required run rate = 282 – (3.2 × 10 / 40)
= 240 / 40
= 6.25

#44 Average Quantitative Aptitude Question

The average of a non zero number and its square is 5 times the number. The number is 

A. 9

B. 17

C. 29

D. 295

Ans: A.Sol.
Let the number be x. Then,
x + x² / 2 = 5x
‹=› x² – 9x = 0
‹=› x (x - 9) = 0
‹=› x = 0 or x = 9.
So, the number is 9.

#59 Average Quantitative Aptitude Question

The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is 

A. 25
B. 27
C. 30
D. 35

Ans: D.Sol.
Therefore excluded number 
= (27 × 5) - ( 25 × 4) 
= 135 – 100 
= 35.

#18 Average Quantitative Aptitude Question

A batsman makes a score of 87 runs in the 17th inning and thus increases his average by 3. find his average after 17th inning. 

Sol. Let the average after 17th inning = x.
Then, average after 16th inning = (x - 3)
∴ 16(x - 3) + 87 = 17x or x = (87 - 48) = 39

#63 Average Quantitative Aptitude Question

Out of the five integral numbers C is the average of A and D.  B is greater than C and less than D.Also B is the average of A and E . The middle most number in the sequence 

A) A
B) B
C) C
D) D

Answer: B) B 

Explanation:

     D _  C  _ A          --------(1)

     D > B > C           --------(2)

from (1) and (2)

     D > B > C > A   ---------(3)

 

Again      E _ B _ A

But B > A, from (3)

So          E > D > B > C > A      [ Since B is the average of E and A so it is eqidistant from both E and A]

#67 Average Quantitative Aptitude Question

The average of any 5 consecutive odd natural numbers is k . If two more such numbers , just next to the previous 5 numbers are added , the new average becomes

A) 2(k+1)
B) 2k-3
C) 2k+1
D) k+2

Answer: D) k+2 

Explanation:

The 5 consecutive odd numbers whose average is k are  (k-4), (k-2), k, (k+2), (k+4)

Again the average of (k-4), (k-2), k, (k+2), (k+4), (k+6), (k+8) is (k+2)

#73 Average Quantitative Aptitude Question

The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years, The ratio of the number of boys to the number of girls in the class is :

A) 1 : 2
B) 2 : 3
C) 3 : 4
D) 4 : 5

Answer: B) 2 : 3 

Explanation:

 Let the ratio be k : 1. Then,

k * 16.4 + 1 * 15.4 = (k + 1) * 15.8

<=> (16.4 - 15.8) k = (15.8 - 15.4)  <=> k =  0.4/0.6 = 2/3.

Required ratio  = 2/3 : 1 = 2 : 3.

#38 Average Quantitative Aptitude Question

The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then :

A) x = y + z
B) 2x = y + z
C) 3x = 2y - 2z
D) none of these

Answer: B) 2x = y + z 

Explanation:

Clearly, we  have : x = (3y + 3z ) / 6 or 2x = y + z.

#52 Average Quantitative Aptitude Question

Of the following, which is greater than ½ ?

Indicate ALL such fractions.

A) 2/5
B) 4/7
C) 4/9
D) 5/11

Answer: B) 4/7 

Explanation:

One way to deal with fractions is to convert them all to decimals. 

In this case all you would need to do is to see which is greater than 0.5.

Otherwise to see which is greater than ½, double the numerator and see if the result is greater than the denominator. In B doubling the numerator gives us 8, which is bigger than 7. 

#78 Average Quantitative Aptitude Question

What is the average of four tenths and five thousandths

A) 25002
B) 2502
C) 0.2025
D) none

Answer: C) 0.2025 

Explanation:

Four tenths = 0.4

Five thousandths = 0.005

The average is (0.4 + 0.005)/2 = 0.2025

#56 Average Quantitative Aptitude Question

A team of 8 persons joins in a shooting competition. The best marksman scored 85 points. If he had scored 92 points, the average score for the team would have been 84. The number of points, the team scored was :

A) 665
B) 657
C) 658
D) 678

Answer: A) 665 

Explanation:

Let the total score be x.

(x + 92 - 85) / 8 = 84.

So,  x + 7 = 672   => x = 665.

The average of six numbers is 3.95. The average of two of them is 3.4, while the average of the other two is 3.85. What is the average of the remaining two numbers ?

A) 3.6
B) 4.6
C) 6.5
D) 7.3

 Answer: B) 4.6 

Explanation:

 Sum of the remaining two numbers = (3.95 * 6) - [(3.4 * 2) + (3.85 * 2)]

                                                   = 23.70 - (6.8 + 7.7) = 23.70 - 14.5 = 9.20.

Required average = (9.2 / 2) =  4.6.

#84 Average Quantitative Aptitude Question

The average price of three items of furniture is Rs. 15000. If their prices are in the ratio 3:5:7, the price of the cheapest item is :

A) 6000
B) 7000
C) 8888
D) 9000

Answer: D) 9000 

Explanation:

Let their prices be 3x,  5x and 7x.

Then, 3x + 5x + 7x = (15000 * 3) or x = 3000.

Cost of cheapest item = 3x = Rs. 9000.

@8

  Average Question & Answers 

Average

Quantitative aptitude questions are asked in many competitive exams and placement exam. Average is a category in Quantitative Aptitude. Quantitative aptitude questions given here are extremely useful for all kind of competitive exams like Common Aptitude Test (CAT), MAT, GMAT, IBPS Exam, CSAT, CLAT, Bank Competitive Exams, ICET, UPSC Competitive Exams, CLAT, SSC Competitive Exams, SNAP Test, KPSC, XAT, GRE, Defense Competitive Exams, L.I.C/ G. I.C Competitive Exams, Railway Competitive Exam, TNPSC, University Grants Commission (UGC), Career Aptitude Test (IT Companies) and etc., Government Exams etc.

We have a large database of problems on "Average" answered with explanation. These will help students who are preparing for all types of competitive examinations.

The average of runs of a cricket player of 10 innings was 32. How many runs must he make in his next innings so as to increase his average of runs by 4 ?

A) 76B) 79C) 85D) 87

 Answer & ExplanationAnswer: A) 76 

Explanation:

Average = total runs / no.of innings = 32 

So, total = Average x no.of innings = 32 x 10 = 320.

 

Now increase in avg = 4runs. So, new avg = 32+4 = 36runs 

Total runs = new avg x new no. of innings = 36 x 11 = 396 

Runs made in the 11th inning = 396 - 320 = 76

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

1

10 years ago, the average age of a family of 4 members was 24 years. Two children having been born (with age diference of 2 years), the present average age of the family is the same. The present age of the youngest child is :

A) 1B) 2C) 3D) 4

 Answer & ExplanationAnswer: C) 3 

Explanation:

Total age of 4 members, 10 years ago = (24 x 4) years = 96 years.

Total age of 4 members now = [96 + (10 x 4)] years = 136 years.

Total age of 6 members now = (24 x 6) years = 144 years.

Sum of the ages of 2 children = (144 - 136) years = 8 years.

Let the age of the younger child be  years.

Then, age of the elder child = years.

So, 

Age of younger child  =  3 years.

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

6

If the arithmetic mean of seventy-five numbers is calculated, it is 35. if each number is increased by 5, then mean of new numbers is :

A) 30B) 40C) 50D) 60

 Answer & ExplanationAnswer: B) 40 

Explanation:

Let the numbers are 

By Hypothesis , ......(i)

 

Mean of new numbers = 

 By (i) 

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

16

In an examination, a pupil's average marks were 63 per paper. If he had obtained 20 more marks for his Geography paper and 2 more marks for his History paper, his average per paper would have been 65. How many papers were there in the examination ?

A) 8B) 9C) 10D) 11

 Answer & ExplanationAnswer: D) 11 

Explanation:

Let the number of papers be x. Then, 63x + 20 + 2 = 65x or 2x = 22 or x = 11.

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

3

The average age of a husband and his wife was 23 years at the time of their marriage. After  five years they have a one-year old child. The average age of the family now is : 

A) 25B) 23C) 19D) 18

 Answer & ExplanationAnswer: C) 19 

Explanation:

Sum of the present ages of husband, wife and child = (23 * 2 + 5 * 2) + 1 = 57 years.

Required average = (57/3) = 19 years.

@7

Average Question & Answers 

The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero ?

A) 0B) -1C) 1D) none of these

 Answer & ExplanationAnswer: A) 0 

Explanation:

Average of 20 numbers = 0.

Sum of 20 numbers = (0 * 20) = 0.

It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (- a).

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

11

A grocer has a sale of Rs 6435, Rs. 6927, Rs. 6855, Rs. 7230 and Rs. 6562 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of Rs, 6500 ?

A) 4991B) 5467C) 5987D) 6453

 Answer & ExplanationAnswer: A) 4991 

Explanation:

 Total sale for 5 months = Rs. (6435 + 6927 + 6855 + 7230 + 6562) = Rs. 34009.

Required sale = Rs.[(6500 x 6) - 34009]

= Rs. (39000 - 34009)

= Rs.  4991.

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

14

After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. What is the difference between the ages of the replaced and the new member ?

A) 12B) 13C) 14D) 15

 Answer & ExplanationAnswer: D) 15 

Explanation:

i) Let the ages of the five members at present be a, b, c, d & e years. 

And the age of the new member be f years. 

ii) So the new average of five members' age = (a + b + c + d + f)/5 ------- (1) 

iii) Their corresponding ages 3 years ago = (a-3), (b-3), (c-3), (d-3) & (e-3) years 

So their average age 3 years ago = (a + b + c + d + e - 15)/5 = x ----- (2) 

==> a + b + c + d + e = 5x + 15 

==> a + b + c + d = 5x + 15 - e ------ (3) 

iv) Substituting this value of a + b + c + d = 5x + 15 - e in (1) above, 

The new average is: (5x + 15 - e + f)/5 

Equating this to the average age of x years, 3 yrs, ago as in (2) above, 

(5x + 15 - e + f)/5 = x 

==> (5x + 15 - e + f) = 5x 

Solving e - f = 15 years. 

Thus the difference of ages between replaced and new member = 15 years.

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

18

 A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is :

A) 45B) 40C) 39D) 37

 Answer & ExplanationAnswer: B) 40 

Explanation:

Let there be x pupils in the class.

Total increase in marks = (x * 1/2) = x/2.

x/2 = (83 - 63) => x/2 = 20 => x = 40.

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Subject: Average - Quantitative Aptitude - Arithmetic Ability

8

The average of five consecutive odd numbers is 61. What is the difference between the highest and lowest numbers :

A) 4B) 8C) 12D) 16

 Answer & ExplanationAnswer: B) 8 

Explanation:

Let the numbers be x, x + 2, x + 4, x + 6 and x + 8.

Then  [x + (x + 2) + (x + 4) + (x + 6) + (x + 8) ] / 5 = 61.

or 5x + 20 = 305 or x = 57.

So, required difference = (57 + 8) - 57  = 8