Gross profit is equal to revenues minus expenses, or selling price minus cost.
Example: A certain appliance costs a merchant $30. At what price should the merchant sell the appliance in order to make a gross profit of 50 percent of the cost of the appliance?
If s is the selling price of the appliance, then s - 30 = (0.5)(30), or s = $45. The merchant should sell the appliance for $45.