#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.