You will be given a definition of a task first, then some input of the task.
The task is to generate the correct answer for a given math problem.

Problem: i bought two books ; for rs . 500 . i sold one at a loss of 15 % and other at a gain of 19 % and then i found each book was sold at the same price . find the cost of the book sold at a loss ?
Output:
291.6