A sum borrowed under compound interest doubles itself in 10 years. When will it become four times of itself at the same rate of interest?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 20 years
In 10 years the sum becomes 2 times of it, in next 10 years it will become = 2 × 2 = 4 times
Hence sum will be four times of itself in 10 + 10 = 20 years