A sum of money doubles itself in 8 years at a certain rate of simple interest. In how many years will it become four times of itself at the same rate of simple interest ?

Correct option is C

Given:

The sum doubles in 8 years. So, after 8 years, the amount becomes 2P.
Using the formula for simple interest:

Simple Interest = (P x R x T) / 100
And the formula for the final amount:

Amount = P + Simple Interest
We can write the equation for the given condition:

2P = P + (P x R x 8) / 100
Simplifying this equation, we get:

P = (P x R x 8) / 100
Further simplification leads to:

R = 100 / 8 = 12.5%
Now, we need to find the time T when the amount becomes 4P. Using the same formula:

4P = P + (P  x 12.5 x T) / 100
Simplifying:

3P = (P x 12.5 x T) / 100
Solving for T:

T = (3 x 100) / 12.5 = 24