Question

$1+3+5+7+......$
If the sum of the above pattern is 81, then how many terms are present in the above series?

• A. 7
• B. 8
• C. 9
• D. 10

Answer 1

The correct option is C 9

$1+3+5+7+......=N^2$ where N is the number of terms in the series.

We are given the sum is 81.
$⟹N^2=81$
$N=9$

So, there are 9 terms.