A shopkeeper sells an article at $$12\frac{1}{2}$$% loss. If he sells it for Rs. 92.50 more than he gains 6% . What is the cost price of the article ?

$$\eqalign{ & {\text{Let C}}{\text{.P}}{\text{. be Rs}}{\text{. }}x \cr & {\text{Then,}} \cr & {\text{ = }}\left( {106\% {\text{ of }}x} \right) - \left( {87\frac{1}{2}\% {\text{ of }}x} \right) = 92.50 \cr & \Rightarrow 18\frac{1}{2}\% {\text{ of }}x = 92.50 \cr & \Rightarrow x = \left( {\frac{{92.50 \times 100 \times 2}}{{37}}} \right) = 500 \cr & {\text{CP}} = {\text{Rs}}{\text{. }}500 \cr} $$