Question

Mark (✓) against the correct answer:
The selling price of an article is $\frac{6}{5}$ of the cost price. The gain per cent is
(a) 15%
(b) 20%
(c) 25%
(d) 30%

Answer 1

(b) 20%

​ $$\begin{gathered} \mathrm{Let}x\mathrm{be}\mathrm{the}\mathrm{CP}\mathrm{of}\mathrm{the}\mathrm{article}. \\ \mathrm{Then},\mathrm{SP}\mathrm{of}\mathrm{the}\mathrm{article}=\frac{6}{5}x \\ \mathrm{Now},\mathrm{gain}=\left(\mathrm{SP}-\mathrm{CP}\right) \\ =\left(\frac{6}{5}\mathrm{x}-\mathrm{x}\right) \\ =\frac{\mathrm{x}}{5} \\ \therefore \mathrm{Gain}\mathrm{percentage}=\left(\frac{\mathrm{gain}}{\mathrm{CP}}\times 100\right)\% \\ =\left(\frac{{\displaystyle \frac{\mathrm{x}}{5}}}{\mathrm{x}}\times 100\right)\% \\ =\left(\left(\frac{\mathrm{x}}{5}\times \frac{1}{\mathrm{x}}\right)\times 100\right)\% \\ =20\% \end{gathered}$$