Question

$\text{What is the sum of first 11 odd numbers?}$

• A. 121
• B. 115
• C. 107
• D. 93

Answer 1

The correct option is A 121

$\text{The sum of n successive odd natural}\text{numbers starting from 1 is always}\text{equal to}{n}^2.$

$\Rightarrow 1+3+...+n=n^2$

$\text{Hence, the sum of 11 successive odd}\text{nautral numbers is}\Rightarrow 1+3+5+7+9+11+13+15+17+19+21=11\times 11=121$