Question

The difference between the compound interest and the simple interest for a certain sum ofmoney for 3 years at 10% per annum is 31. Find the sum.​

Answer 1

Answer:

Hence the answer is 1000.

Step-by-step explanation:

Let P be the principal.

Value including interest after 36 months at simple interest:

P+ (P X 3x 10/100)

P(1+ 30/100),= P X 130/100. (1)

Compound interest:

=P X 110/100 X 110/100 X 110/100,

=P X 1331/1000. (2)

The difference in interest is 31.

Hence (2) - (1) = 31.

i.e. P X 1331/1000 - P X 1300/1000 = 31

P X 31/1000 = 31.

P = 1000.

Hence the answer is 1000.