Correct Answer - Option 4 : Rs.3067.03
Calculation:
Let amount he borrowed be Rs.m.
Each installment = Rs.2000
⇒ m(1 + 20/100)3 = 2000(1 + 20/100)3-1 + 2000(1 + 20/100)3-2 + 2000(1 + 20/100)3-3
⇒ 1.728m = 2880 + 2400 + 2000
⇒ m = 4212.96
The sum he borrowed is Rs.4212.96.
∴ Compound interest = 4212.96(1 + 20/100)3 - 4212.96 = Rs.3067.03
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Let a be the installment.
P(1 + R/100)n = a(1 + R/100)n-1 + a(1 + R/100)n-2 + a(1 + R/100)n-3 +….+ a