Question

A sum of money doubles itself in 10 years. Find the rate percent per annum.

Answer 1

Given:

Principal = P

Amount = 2P

Time 10 years

Required:

Rate percent per annum.

Step-by-step explanation:

The amount is given as,

`A\text{ = P + I}`

Interest is calculated as,

`\begin{gathered} I\text{ = }(PR*10)/(100) \\ A-P\text{ = }(PR*10)/(100) \\ 2P-P=(PR*10)/(100) \\ \end{gathered}`

The rate of interest is calculated as,

`\begin{gathered} P\text{ = }(PR)/(10) \\ R\text{ = 10} \end{gathered}`

Answer:

Thus the rate of interest is 10%.