A trader bought two horses for Rs. 19500, he sold one at a loss 20% and the other at a profit of 15%. If the selling price of each horse is the same, then their cost prices are respectively ?

Let the CP of horse = Rs. x
Then, CP of second horse = Rs. (19500 - x)
According to the question,
$$\eqalign{ & x \times \frac{{80}}{{100}} = \left( {19500 - x} \right) \times \frac{{115}}{{100}} \cr & \Rightarrow 16x = 23\left( {19500 - x} \right) \cr & \Rightarrow 16x = 448500 - 23x \cr & \Rightarrow 39x = 448500 \cr & \Rightarrow x = \frac{{448500}}{{39}} \cr & \Rightarrow x = {\text{Rs}}{\text{.}}\,11500 \cr} $$
∴ CP of first horse = Rs. 11500
∴ CP of second horse
= Rs. 19500 - 11500
= Rs. 8000