Question

The sum of first 11 terms of the A.P 2, 6, 10, 14,... is .

• A. 242
• B. 240
• C. 424
• D. 244

Answer 1

The correct option is A 242

The sum of n terms of an AP with first term $a$ and common difference $d$ is given by
$S_n=\frac{n}{2}(2a+(n-1\left)d\right)$

$a=2,d=4,n=11$

Hence,
$S_n=\frac{11}{2}\left(2\right(2)+(11-1\left)4\right)$
$S_n=\frac{11}{2}(4+40)$
$S_n=\frac{11}{2}\times 44$
$S_n=242$