Question

If the difference between simple interest and compound interest on a certain sum of money for 3 years at 10% per annum is Rs 31,the sum is

plz solve please​

Answer 1

Given :

A certain amount invested in a simple interest and compound interest account at 10% interest for 3 years.

To Find :

The principal amount of the both account.

Solution :

Let the principal amount = P

In simple interest account

A = P(1 + rt)

   = P( 1 + 0.10 × 3)

   = P( 1.3 )

In compound interest account

A = P( 1 + 0.1 )³

   = P (1.01)³

   = P(1.331)

Difference of interest is 31 Rs.

P(1.331) - P(1.3) = 31

$(1.331p\pm1.3p)=31$

0.031p = 31

p = $\frac{31}{0.031}$

p = 1000 Rs.

The sum is 1000 Rs.