The price the Rafael paid for the camera is 652 dollars which already has a discount which is 20%.
There are a lot of ways to solve it, however, I'll show you the easiest way.
=> 652 dollars is the 80% of the price since it lessen by 20%
=> 652 / 8 = 81.5 is the 10% of the price.
=> 81.5 * 10 = 815 dollars is the original price of the camera.
