Question

Find the sum of $2,7,12,...$to $10$ terms

• A. $160$
  
• B. $245$
• C. $290$
• D. $300$

Answer 1

The correct option is B $245$

Clearly, the given sequence is an AP with first term $a=2$, common difference $d=5$ and $n=10$.
Now,

$S_{10}=\frac{10}{2}[2a+(10-1\left)d\right]$

$=5[2\times 2+9\times 5]$

$=245$