# Find out the time:

At simple interest, a sum becomes 3 times in 20 years. Find the time in which the sum will be double at the same rate of interest?

- 8year
- 10 year
- 12 year
- 14 year

**Answer: (2) 10 years**

**Explanation:-**

A sum becomes 3 times in 20 years,

Given-

Let the principal is P.

Time = 20 years, S I = 3 P – P = 2 P & R = ?

**Formula-**

**Simple Interest = P x R x T/100**

**Where, P = principal , R = rate, & T = time.**

Then, 2 P = P x 20 x R/100

2 = 20 R/100

1 = R/10

R = 10 %.

The sum will be double,

Then, S I = 2 P – P = P , R = 10 % & T = ?

P = P x 10 x T/100

1 = 10 T/100

1 = T/10

T = 10 years

Hence, the answer is (2) 10 years.