# Find the Rate at Which a Sum of Money Will Double Itself in 3 Years, If the Interest is Compounded Annually. - Mathematics

Sum

Find the rate at which a sum of money will double itself in 3 years, if the interest is compounded annually.

#### Solution

Let the rate percent per annum be R.
Then,
$A = P \left( 1 + \frac{R}{100} \right)^n$
$2P = P \left( 1 + \frac{R}{100} \right)^3$
$\left( 1 + \frac{R}{100} \right)^3 = 2$
$\left( 1 + \frac{R}{100} \right) = 1 . 2599$
$\frac{R}{100} = 0 . 2599$
R = 25 . 99
Thus, the required rate is 25 . 99 % per annum.

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#### APPEARS IN

RD Sharma Class 8 Maths
Chapter 14 Compound Interest
Exercise 14.3 | Q 16 | Page 20