An increase of Rs. 3 in the selling price of an article turns a loss of $$7\frac{1}{2}$$% into a gain of $$7\frac{1}{2}$$%. The cost price in (Rs.) of the article is -

$$\eqalign{ & {\text{Let C}}{\text{.P}}{\text{. be Rs}}{\text{. }}x \cr & {\text{Then,}} \cr & 107\frac{1}{2}\% {\text{ of }}x - 92\frac{1}{2}\% {\text{ of }}x = 3 \cr & \Rightarrow \frac{{215}}{{200}}x - \frac{{185}}{{200}}x = 3 \cr & \Rightarrow \frac{{30x}}{{200}} = 3 \cr & \Rightarrow x = 20 \cr} $$