Question

The sum upto 12 terms of the series is $20,25,30,35,.....$

• A. 1050
• B. 1150
• C. 1250
• D. None

Answer 1

The correct option is A 1050

The series is $20,25,30,35,.........$

This series form AP with $a=20$ and $d=5$

The sum upto $12$ terms is given as $\frac{12}{2}\left[2\right(20)+(12-1\left)5\right]6\times [40+55]6\times 95=570$