Question

Find the sum on which the compound interest for 3 years at 10% per annum amounts to Rs 1655

Answer 1

Let P be the principal on which compound interest CI = Rs 1655

CI = P [1 + r/100]^n - P
Where r is rate of interest = 10% and n is period 3 years.

1655 = P [1 + 10/100]^3 - P
1655 = P [1.1]^3 - P

1.1^3 = 1.331

Therefore, 1655 = 1.331P - P = 0.331P

Thus, P = 1655/0.331 = 5000

Therefore, the sum is Rs 5000

Answer 2

C.I = P(1+R/100)T-P
1655=P(1+10/100)3-P
1655=P×11/10×11/10×11/10-P
1655=1331P/1000-P
1655=1331P-1000P/1000
1655=331P/1000
1655000=331P
P=1655000/331P=5000