# What is the least number of complete years in which a sum of money

Interests
What is the least number of complete years in which a sum of money at 20% compound interest will be more than doubled?

- 4
- 5
- 6
- 7

### Answer

If principal amount be P, then we need to find n for the following equation

P(1 + 0.2)^{n} > 2P

(1.2)^{n} > 2

n(log 1.2) > n log 2 (log means log to the base e i.e natural log)

n > (log 2 / log 1.2) > 3.8

So, Complete years = 4

**The correct option is A.**