Quantitative Aptitude • Simple & Compound InterestHard
A sum of money doubles itself in 12 years at compound interest. In how many years will it become 4 times itself?
A. 25 years
B. 36 years
C. 24 years✓ Correct Answer
D. 48 years
💡 Solution & Explanation
With compound interest the sum keeps doubling every 12 years: 2 times after 12 years, 4 times after 24, 8 times after 36, and so on. 4 = 2^2, so it takes 2 doublings: 2 × 12 = 24 years. Multiplying 12 by 4 (48 years) would be the simple-interest way of thinking, which does not apply here.
More Quantitative Aptitude Simple & Compound Interest questions
- At what rate of simple interest per year will a sum of money double itself in 20 years?
- The simple interest on a sum of money at 8% per year for 6 years is ₹11,520. What is the sum?
- In how many years will ₹25,000 earn a simple interest of ₹18,000 at 12% per year?
- The simple interest on a sum of money at 4% per year for 4 years is ₹5,360. What is the sum?
- A sum of money doubles itself in 11 years at compound interest. In how many years will it become 16 times…