If a sum doubles itself in 5 years at simple interest, in how many years will the sum become five times itself?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 20 years
Under simple interest the interest is the same every year, so the total interest grows in proportion to the time.
The sum doubles in 5 years, so the interest in 5 years equals the sum itself (1 times the principal)
To become five times, the sum must earn 4 times the principal as interest
Time needed: \(4\times5=20\) years