Ketan has two grandsons Mahesh and David. 15 year old Mahesh gets some money from Ketan’s wealth and 16 year old David gets rest of the money. But Mahesh and David will get money only when they turn 22 years old. Till then the money is in a bank getting interest at rate 10% compounded annually. When both turn 22, they receive the same amount. How much had Ketan given David (in ₹) initially, if total money with Ketan was ₹25200?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 13200.
Mahesh: 7 years → M × (1.1)7
David: 6 years → (25200 - M) × (1.1)6
Both amounts equal at age 22:
M × (1.1)7 = (25200 - M) × (1.1)6
Divide both sides by (1.1)6:
M × 1.1 = 25200 - M
2.1M = 25200
M = 12000 → David got: 25200 - 12000 = ₹13200