Question

During a sale at a bookstore, Joseph buys a book at full price. He is given a 50 percent discount on a second book of equal or less value. If Joseph buys two books that have a full price of $15 and $10, by what percent is the total cost of the two books reduced during the sale?

Answer 1

Joseph is going to pay full price for the higher priced book so we start with 15 dollars.  Then he pays 50% of the second book which is 10 dollars, so we find 50% of 10 and then add it to 15...

15 + 50% x 10 =
15 + .5 x 10 =
15 + 5 = 20

He pays a total of $20