Question

a sum of money doubles itself in 8 years. find the rate of interest

Answer 1

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Here is your answer.
Let the Sum is x
A = 2x

SI = A - P
= 2x - x
= x
T =8 years
Let Rate of interest is r %

As we know the formula
SI = PRT/100
$x = \frac{x \times r \times 8}{100} \\ \\ r = \frac{x \times 100}{x \times 8} \\ \\ r = 12.5\%$
Therefore Rate of interest is 12.5%

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Answer 2

Hi friends

Here is your answer

Let Sum = x
A = 2x
so SI = x
T = 8 years
Now
Rate of interest = SI × 100/PT
$= \frac{x \times 100}{x \times 8} \\ = 12.5\%$
Hope it helps you

@ MSD