# A certain sum amounts to Rs. 7000 in 2 years and to Rs. 8000 in 3 years. Find the sum ?

A certain sum amounts to Rs. 7000 in 2 years and to Rs. 8000 in 3 years. Find the sum ?

A. Rs 6959.37

B. Rs 6459.37

C. Rs 5359.37

D. Rs 5759.37

**Answer : **C. Rs 5359.37...

## Explanation :

Amount = Rs. 7000, Time = 2 years

Amount = Rs. 8000, Time = 3 years

To calculate sum, we must first calculate rate of interest.

Simple interest = PRN / 100

S.I. on Rs. 7000 for 1 year = Rs. (8000 – 7000) = Rs. 1000

1000 = 7000 × R × 1 / 100

R = 11 23/7%

Let sum be Rs. X

7000 = P [ 1 + ( 100 / 7 × 100 ) ]^{2}

8 / 7 × 8 / 7 × P = 7000

P = 5359.37