Question

Mean of first ‘n’ natural numbers is ……………

A) n

B) n/2

C) n-1/2

D) n+1/2

Answer 1

Correct option is: D) \(\frac {n+1}2\)

First n natural numbers are 1, 2, 3,.....,.n

Mean = \(\frac {sum\, of \,first \,n \,natural \,numbers}n\) = \(\frac {1+2+3+.....+n}n\)

= \(\frac {\frac {n(n+1)}2}{n} = \frac {n (n+1)}{2n} = \frac {n+1}2\)

Hence, mean of first n natural numbers is \(\frac {n+1}2\).

Answer 2

Correct option is: D) \(\frac{n+1}{2}\)