A certain sum triples in 8 years under compound interest. How many years will it take for that sum to grow to nine times its original value?
Show answer & explanation
Correct answer: A
Explanation
Amount in 8 years = 3 times
9 times = 3 × 3
First 3 times → 8 years
Second 3 times → 8 years
Total time = 8 + 8 = 16 years