#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.