Question

a certain sum amounts to rupees 5292 in 2 years and with 555 6.60 in 3 years interest being compounded annually find the rate of interest and the original sum

Answer 1

Please refer the above photograph for the used process.
Hope this will be helping you

WARM REGARDS
Sahil khirwal.

Answer 2

Given:

Sum amounts to rupees 5292 in 2 years and with 5556.60 in 3 years.

To Find:

Rate of interest and the original sum.

Solution:

1) There is the direct way to find the rate of the interest in these type of the questions of the compound interest is given by:

amount in 3rd year / amount in 2nd year

• 5556.6/5292

• 21/20

2) This is the scaling factor of the rate of the interest for the one year and rate is obtained as 1/20  which is 5%.

3) The original sum is given by the given formula

• $A = P(1+\frac{R}{100})^{T}$

• $5292 = P(1+\frac{5}{100})^{2}$

• P = 5292×20×20/21×21

• P = 4800

Rate of interest and the original sum are 5% and 4800 respectively.