Question

a sum of money Doubles itself in 10 years what is rate of interest

Answer 1

let principal=x,
then
amount=2x,

so
interest=2x-x=x,

therefore
x=x×r×10/100,

r=10%

Answer 2

Hi..!

Let the sum be Rs x .

Then , amount = Double the sum = Rs 2x .

Thus, SI = A - P = 2x - x = Rs x

Time = 10 years .

Using formula , R% = SI * 100 / T * P = x * 100 / 10 * x = 10% p.a

Answer : Hence, rate of interest = 10% p.a .

Thanks...!!!!