Multiple choice

A sum of amount becomes 3 times in 8 years at the rate of compound interest compounded annually. In how many years will it become 81 times?

  1. 24

  2. 40

  3. 32

  4. 16
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Amount becomes 3 times in 8 years. In compound interest, if A becomes 3 times in 8 years, it becomes 3^2 = 9 times in 16 years. To reach 81 = 3^4 times, it takes 4 × 8 = 32 years.

Keep practicing — related questions