Arithmetic mean of first n natural number

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8. Sequences and Series

easy

The arithmetic mean of first $n$ natural number

A

$\frac{{n - 1}}{2}$

B

$\frac{{n + 1}}{2}$

C

$\frac{n}{2}$

D

$n$

Solution

(b) $A.M. $$ = \frac{{1 + 2 + 3 + …… + n}}{n} = \frac{{\frac{1}{2}n(n + 1)}}{n} = \frac{{n + 1}}{2}$.

Standard 11

Mathematics

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