A box of cereal is priced at x cents per box. A customer has a coupon for 15 cents off. If the store reduces prices by doubling the value of each coupon, how much, in cents, does the customer pay for the box of cereal?
Explanation
Because the coupon has double value, the reduction is 2*15 = 30 cents. The cost of the cereal is x − 30 cents.