Question

A man saves 18% of his monthly income. If he saves Rs 3780 per month, what is his monthly income?

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{Rs}x\mathrm{be}\mathrm{his}\mathrm{monthly}\mathrm{income}. \\ \mathrm{His}\mathrm{savings}=18\%\mathrm{of}\mathrm{Rs}\mathrm{x} \end{gathered}$$

$$\begin{gathered} =\mathrm{Rs}\left(x\times \frac{18}{100}\right) \\ =\mathrm{Rs}\frac{9x}{50} \end{gathered}$$
$$\begin{gathered} \mathrm{Now},\frac{9x}{50}=3780 \\ \Rightarrow x=\mathrm{Rs}\left(3780\times \frac{50}{9}\right) \\ \Rightarrow x=\mathrm{Rs}21000 \\ \therefore \mathrm{His}\mathrm{monthly}\mathrm{income}\mathrm{is}\mathrm{Rs}.21000. \end{gathered}$$