Group D (4x5=20)
34. A sum of money amounts to Rs. 19361 in 2 years and Rs. 23425.60in
4 years at the rate of compound interest annually. Find the rate of
compound interest and the sum.

rate of  compound interest: 10%

the sum: Rs. 16000.83

Step-by-step explanation:

compound interest: A = P (1 + r)ⁿ   P: initial sum   r: annual interest  n: period

23425.60 = P (1 + r)⁴                (a)

19361 = P (1 + r)²                       (b)

A/b:   23425.60 / 19361 = (1 + r)²

(1 + r)² = 1.21

1 + r = 1.1

r = 0.1            (10%)

P = 19361 / 1,21 = 16000.83