Question: A sum of money placed at compound interest (compounding annually) doubles itself in 10 years. find the time in which it will amount to 4 times itself.
- 10 years
- 15 years
- 14 years
- 20 years
Answer: 20 years
Solution:
Time is directly proportional to amount.
As amount is doubled in 10 years so amount will 4 times in next 10 years.