Question

At what rate percent per annum will a sum of money be double in 20 years?

Answer 1

Given:

• A sum of money be double.
• Time = 20 years

To Find:

• Rate = ?

Solution:

Let the principal= P,A = 2P

S.I. = 2P - P = P

T = 20 years

$\sf \rightarrow \: r = \frac{p \times 100}{p \times 20} \\ \\ \sf \rightarrow \: r = 5\%$

• Hence,rate = 5%