A) 25% profit
B) 40% profit
C) 50% profit
D) 125% profit
Correct Answer: D
$ \Rightarrow $ $ SP=\frac{100-10}{100}\times x=\frac{9x}{10} $
$ \therefore $ Profit per cent $ =\frac{SP-CP}{CP}\times 100 $ % $ =\frac{\frac{9x}{10}-\frac{2x}{5}}{\frac{2}{5}x}\times 100 $ % $ =\frac{( \frac{9-4}{10} )x}{\frac{2}{5}x}\times 100 $ % $ =\frac{5}{10}\times \frac{5}{2}\times 100=125 $ %