Question

A certain sum of money doubles itself in 5 years. Find the time taken for the same sum
to become five times of itself at the same rate of interest p.a.​

Answer 1

Answer:

Let the Principal sum taken (P) be x

Time period (T)- 5.5years

The sum will be doubled therefore Interest (SI) generated will be x

Therefore by the formula for Simple Interest

SI=(P×R×T)/100

x=(x×R×5.5)/100

Therefore R=100/5.5=18.18

THUS, the Rate of Interest is 18.18 %per annum