# In How much time? If

A certain sum of money doubles itself in 5 years at S.I. in how many years it becomes 7 times itself?

- 10 years
- 20 years
- 30 years
- 32 years

**Answer: (c) 30 years
Explanation:-**

Let the principal is X

According to question, money doubles itself in 5 years

then S I = 2X – X = X

Now, we can find the rate

X = (X x R x 5)/100

R = 20%

Again X becomes 7 times itself, then S I = 7X – X = 6X

6X = (X x 20 x T)/100

T = 30 years

Hence, in 30 years it becomes 7 times itself.