Question

Find the sum of integers from $1$ to $35$.

• A. $1160$
• B. $630$
• C. $1360$
• D. $1460$

Answer 1

The correct option is B $630$

Given, $n=35$
We know $S_n=\frac{n}{2}[n+l]$
$S_{35}=\frac{35}{2}[35+1]$
$S_{35}=\frac{35\left[36\right]}{2}$
$S_{35}=\frac{1260}{2}=630$