Question

Find the sum of the arithmetic progression : $-26,-24,-22,...$ to $36$ terms.

• A. $324$
• B. $314$
• C. $389$
• D. $349$

Answer 1

The correct option is A $324$

Given series is $-26,-24,-22,...$ to $36$ terms

Here $a=-26,d=2$ and $n=36$.

Now, $S_n=\frac{n}{2}[2a+(n-1\left)d\right]$

So, $S_{36}=\frac{36}{2}\left[2\right(-26)+(36-1)\times 2]$

$=18[-52+70]$

$=18\times 18$

$=324$