Rs 7200 becomes Rs 9504 at a certain rate of simple interest in 4 years. If the rate of interest were 2% less, what would the amount be at the end of 6 years?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Rs 9792
First find the rate from the given amount, then change the rate and work out the interest for 6 years.
Interest in 4 years \(=9504-7200=2304\)
Rate \(\displaystyle =\frac{2304\times100}{7200\times4}=8\%\)
New rate \(=8-2=6\%\)
Interest for 6 years \(\displaystyle =\frac{7200\times6\times6}{100}=2592\)
Amount \(=7200+2592=9792\)
The amount would be Rs 9792.
Why the other options are incorrect
Option (1) Rs 10656 — Incorrect. Rs 10656 would mean interest of Rs 3456 in 6 years, that is a rate of 8%, not 6%.
Option (2) Rs 9360 — Incorrect. Rs 9360 would mean interest of Rs 2160 in 6 years, that is a rate of 5%, not 6%.
Option (3) Rs 10224 — Incorrect. Rs 10224 would mean interest of Rs 3024 in 6 years, that is a rate of 7%, not 6%.