You buy 3 books that each cost the same amount and a magazine all for $55.99 you know the magazine costs $1.99. How much does each book cost ? Equation?!
The 3 books that you buy will cost 18 dollars a piece. You take how much you spend minus the costs you already know. Then what ever is left then you take what you need to find and divide that by the total that you have found.
