A retailer sold an appliance for $100. If the retailer's gross profit on the appliance was 25 percent of the retailer's cost for the appliance, how many dollars was the retailer's gross profit?	Choose the correct choice from the following answers.
A) $ 10 B) $ 16 C) $ 20 D) $ 24 E) $ 25

Rationale: let p be the original price paid by the retailer . 1.25 * p = 100 p = 80 the profit is $ 20 . the answer is c .
Answer: C