Question

The least number of complete years in which a sum of money put at 40% compound interest will be more than doubled is

• A. 1 year
• B. 2 year
• C. 3 years
• D. 4 years

Answer 1

The correct option is C 3 years

The condition in which the value of P will become 2P is given by:

$P*{\left(1+\frac{R}{100}\right)}^T>2P$
(cancelling P on both the sides)

${\left(1+\frac{R}{100}\right)}^T>2{\left(1+\frac{40}{100}\right)}^T>2{(1.4)}^T>2\mathrm{For}T=3,\mathrm{the}\mathrm{condition}{(1.4)}^T>2\mathrm{will}\mathrm{be}\mathrm{true}.\mathrm{Hence}\mathrm{the}\mathrm{answer}\mathrm{is}3.$