Question

How long will it take a certain sum of money to triple itself at $13\frac{1}{3}\%$ per annum simple interest?

Answer 1

Let Principal be $P$. Rate of interest (R) is $13\frac{1}{3}\%$. Let Time (T) be $T$.

Now, according to the question,

Amount $\left(A\right)=3\times P$

$\therefore SI=A-P=3P-P=2P$

$\Rightarrow SI=\frac{PRT}{100}$

$\Rightarrow 2P=\frac{P\times 40\times T}{3\times 100}$

$\Rightarrow \frac{2P\times 300}{P\times 40}=T$

$\therefore T=15$ years