Question 957520
profit = revenue - cost.


rate of profit = (revenue - cost) / cost


percent profit = rate of profit * 100.


if you buy it for 1 and sell it for 3, then your rate of profit = (3 - 1) / 1 = 2/1 and your percent profit = 200%.


if you buy it for 1 and sell it for 5, then your rate of profit = (5 - 1) / 1 = 4 / 1 and your percent profit = 400%.


if you buy it for 5 and sell it for 1, then your rate of profit = (1 - 5) / 5 = -4 / 5 and your percent profit = -400/5 = -80%.


a negative profit is the same as a loss.


a profit of -80% is a loss of 80%.