Average of n numbers is a. The first number is increased by 2, second one is increased by 4, the third one is increased by 8 and so on. The average of the new numbers is -

Answer: Option A

Series:- a, a + 2, a + 4.....
Sum = na + 2 + 4 + ..... upto n terms
Sum = na + S_n
$$S_n=\frac{2\left(2^n-1\right)}{2-1}$$
Average = $$a+\frac{2\left(2^n-1\right)}{n}$$