A sum of money doubles itself in 4 years at simple interest. In how much time will it become 7 times at the same rate of interest?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 24 years
Amount = 2(Principal) (In 4 years)
T= 4 years
Required Amount = 7(Principal)
Simple Interest = (P × R × T)/100
A = P + S.I.
If A = 2P
2P - P = S.I.
S.I. = Principal
P = (P × R × 4)/100
R = 25%
When Amount = 7 times of Principle
S.I. = 6P
6P = (P × 25 × T)/100
T = 600/25 = 24 years