Question

if in the 2 years at simple interest the principal increased by 10% then what will be the compound interest earned on rupees 1000 for 2 years at the same rate of interest

Answer 1

In 2 years P increases by 10 %

Originally P became P + 10/100 × P

                                = P + P/10

                                = ( 10 P + P ) / 10

                                = 11 P / 10

11 P / 10 is the Amount .

Amount = P + I

P + I = 11 / 10 P

==> P + P R T / 100 = 11 / 10 P

==> P ( 1 + RT /100 ) = 11/10 P

Cancel P both sides :

==> 1 + RT / 100 = 11/10

==> RT/100 = 11/10 - 1

==> RT/100 = 1/10

==> RT = 10

Here T = 2 years :

==> 2 R = 10

==> R =10/2 %

==> R = 5%

RATE OF INTEREST

The rate of interest is 5 %

COMPOUND INTEREST :

A = P  ( 1 + R / 100 )²

= > A = 1000 ( 1 + 5 / 100 )²

= > A = 1000 ( 1 + 1 / 20 )²

= > A = 1000 × ( 21 / 20 )²

= > A = 1000 × 441 / 400

= > A = 2.5 × 441

= > A = 1102.5

ANSWER :

The amount is Rs 1102.5

Sorry for late =_=