Shortcut Trick
For equal amounts in Compound Interest, the ratio of shares is inversely proportional to their multiplying factors (1 + R/100)T.
Time difference = 14 − 13 = 1 year.
Ratio of Anand's share to Anil's share = (1 + 8/100)1 = 108/100 = 27/25.
Total ratio parts = 27 + 25 = 52 parts → ₹1612.
Anand's share = 27 × (1612 ÷ 52) = 27 × 31 = ₹837.
∴ The correct answer is ₹837.
Alternate Method
Given:
Total amount distributed = ₹1612
Rate of interest (R) = 8% p.a. compounded annually
Anand's investment time (T1) = 13 years
Anil's investment time (T2) = 14 years
Total: ₹1612
Anand: ₹x
Time: 13 yrs @ 8%
Anil: ₹y
Time: 14 yrs @ 8%
Equal Final Amount
Formula Used:
Amount in Compound Interest, A = P × (1 + R/100)T
Calculations:
Let the amount given to Anand be x and the amount given to Anil be y.
⇒ x + y = 1612
Since the final amounts received by both are equal:
⇒ x × (1 + 8/100)13 = y × (1 + 8/100)14
⇒ x / y = (1 + 8/100)14 / (1 + 8/100)13
⇒ x / y = (1 + 8/100)1
⇒ x / y = 108 / 100 = 27 / 25
The ratio of Anand's share to Anil's share = 27 : 25
⇒ Sum of ratio parts = 27 + 25 = 52 parts
⇒ 52 parts = 1612
⇒ 1 part = 1612 ÷ 52 = 31
Since we need to find Anand's share (which is 27 parts):
⇒ Anand's share = 27 × 31 = 837
∴ The correct answer is ₹837.
Additional Information
Compound Interest Formula
Amount = P × (1 + R/100)T, where P is the principal, R is the rate of interest, and T is the time period.
Equal Amounts in Compound Interest
When a sum is divided into two parts P1 and P2 invested for T1 and T2 years respectively to get equal amounts, the ratio of principals is given by P1/P2 = (1 + R/100)T<sub>2</sub>−T<sub>1</sub>.
Difference between CI and SI for 2 years
The difference between compound interest and simple interest for two years on a principal P at an annual rate R is given by D = P × (R/100)2.