Question

In how many years certain sum amount to double the principal at the rate of 10 %

Answer 1

net profit % = year 1 + year 2 + year 1 * year 2 / 100
10 + 10 + 10 * 10 / 100
21 %

Answer 2

Hi ,

Let the principal = Rs P

Amount = A = Rs 2P

Time = T years

Rate of interest = R = 10%

We know that

A = P( 1 + TR/100 )

2P = P ( 1 + 10T/100 )

2P / P = 1 + T / 10

2 = 1 + T / 10

2 - 1 = T / 10

1 = T/10

10 = T

Therefore ,

In 10 years P becomes double.

I hope this helps you.

:)