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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