Cost Price (C.P.): The price at which an article is purchased. This is your expense.
Selling Price (S.P.): The price at which the article is sold to the customer/buyer. This is your earning.
On comparing C.P. and S.P., the following three cases arise:
Case I: If C.P. < S.P., the sale is profitable and Profit = S.P. – C.P.