Discussion

At what rate per cent per annum will the simple interest on a sum of money be \( \dfrac{2}{5} \) of the sum in 10 years?

Answer: A

\[ \text{SI} = \frac{P \times R \times T}{100} \]

\[ \frac{2}{5}P = \frac{P \times R \times 10}{100} \]

The \( P \) cancels:

\[ \frac{2}{5} = \frac{10R}{100} = \frac{R}{10} \quad\Longrightarrow\quad R = 4\% \]

Checking: 4% for 10 years gives 40% of the sum, which is \( \tfrac{2}{5} \).

No comment is present. Be the first to comment.

Loading…