The simple interest received on a sum for 40 years is 2/5 of the sum. What is the annual rate of interest?

Correct option is B

Given:
Simple interest = 2/5 of sum in 40 years
Formula Used:
Simple Interest = $$\frac{P × R × T }{ 100}$$​​
Solution:

Let the Principal amount be P
2/5 P = 40PR/100
R = 1%