### Theory:

To find the profit or loss percentage, we can use the following formulas:

1. To determine the profit percentage:

If the profit and the cost price of the product are given, we can find the profit percentage.

Profit $$\% =$$ $$\frac{\text{Profit}}{\text{Cost price}}$$$$\times100$$

2. To determine the loss percentage:

If the loss and the product's cost price are given, we can find the loss percentage.

Loss $$\% =$$ $$\frac{\text{Loss}}{\text{Cost price}}$$$$\times100$$

If any two values are known in the above formulas, we can figure out the other values by simply rearranging the formulas.