Question

No.6 fast tommorow exam
Q.6. How long will it take a certain sum of money to triple itself at $13\frac{1}{3}\%$ per annum simple interest?

Answer 1

Dear student,

$$\begin{gathered} LetthePrincipalbeP \\ Amountaftertimetbe3P \\ Amount=P+SI \\ \Rightarrow 3P=P+\frac{PRT}{100} \\ \Rightarrow 2P=\frac{PRT}{100} \\ \Rightarrow 2=\frac{40\times t}{300} \\ \Rightarrow t=\frac{2\times 300}{40} \\ \Rightarrow t=\frac{1\times 300}{20} \\ \Rightarrow t=15years \\ thus,after15yearssumofmoneytriplesitself. \end{gathered}$$
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