42nd B.P.S.C. (Pre) 1997-98
Find the average of first ten prime numbers—
a12.7
b13
c12.9✓ Correct
d12.8
Explanation
The first ten prime numbers are—2, 3, 5, 7, 11, 13, 17, 19, 23, 29 Average = $\frac{2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29}{10}$ = $\frac{129}{10}$ = 12.9
general-mental-ability