in what time will a sum of money double itslelf , the rate of interest p a being 20% - Maths -

Question

in what time will a sum of money double itslelf , the
rate of interest p a being 20%?

Lalit Mehra · Accepted Answer

Dear Student!

Let the sum of money be Rs P and the sum of money doubles itself after the time period, n years.

Given, r = 20 and A = 2P

Simple interest on the sum of money, Rs P at r % p.a. for n years is given by, $S . I . = \frac{P \times r \times n}{100}$

We know that, Amount = Principle + S.I.

∴ A = P + S.I.

$\Rightarrow 2 P = P + \frac{P \times 20 \times n}{100} \Rightarrow \frac{P n}{5} = 2 P - P = P \Rightarrow \frac{n}{5} = 1 \Rightarrow n = 5$

Thus, the sum of money doubles itself after 5 years.

Cheers!

in what time will a sum of money double itslelf , the rate of interest p.a being 20%?