A shopkeeper offered a discount of 15% on the labelled price. By selling an article for Rs. 340 after giving discount he earned a profit of 13¹/₃% . What would have been the percent profit earned if no discount was offered?

Explanation:-

$$\eqalign{ & {\text{S}}{\text{.P}}{\text{.}} = {\text{Rs}}{\text{.340}}{\text{.}} \cr & {\text{Let marked price be Rs}}{\text{. }}x{\text{.}} \cr & {\text{Then,}} \cr & {\text{ = 85}}\% {\text{ of }}x = {\text{340}} \cr & \Rightarrow x{\text{ = }}\left( {\frac{{340 \times 100}}{{85}}} \right) = 400. \cr & {\text{Cost Price}} \cr & = {\text{Rs}}{\text{.}}\left( {100 \times \frac{3}{{340}} \times 340} \right) \cr & = {\text{Rs}}{\text{. 300}}{\text{.}} \cr & {\text{Now, C}}{\text{.P}}{\text{. = Rs}}{\text{. 300}}{\text{.}} \cr & {\text{S}}{\text{.P}}{\text{.}} = {\text{Rs}}{\text{. 400}}{\text{.}} \cr & \therefore {\text{ Required profit }}\% \cr & = \left( {\frac{{100}}{{300}} \times 100} \right)\% \cr & = 33\frac{1}{3}\% . \cr}$$