Question

Solve this:
Q.2. If 50 % of (x - y) = 30 % of (x + y), then what percent of 'x' is 'y'?

Answer 1

Dear student
$$\begin{gathered} 50\%\mathrm{of}(\mathrm{x}-\mathrm{y})=30\%\mathrm{of}(\mathrm{x}+\mathrm{y}) \\ \Rightarrow \frac{50}{100}\times \left(\mathrm{x}-\mathrm{y}\right)=\frac{30}{100}\times (\mathrm{x}+\mathrm{y}) \\ \Rightarrow \frac{5}{\cancel{10}}\left(\mathrm{x}-\mathrm{y}\right)=\frac{3}{\cancel{10}}(\mathrm{x}+\mathrm{y}) \\ \Rightarrow 5\mathrm{x}-5\mathrm{y}=3\mathrm{x}+3\mathrm{y} \\ \Rightarrow 2\mathrm{x}=8\mathrm{y} \\ \Rightarrow \mathrm{x}=4\mathrm{y} \\ \mathrm{Therefore},\mathrm{required}\mathrm{percentage}=\frac{\mathrm{y}}{\mathrm{x}}\times 100 \\ =\frac{\mathrm{y}}{4\mathrm{y}}\times 100 \\ =25\% \end{gathered}$$
Regards