Chapter 5, Problem 34AT

One special type of ratio is known as a rate. A rate is a ratio that compares two quantities that have different units, such as miles per hour, calories per serving, pounds per square inch, and price per unit. In consumer economics, expressing prices as “price per unit” allows us to determine the “best buy” when comparing various shopping choices. All else being equal, the best buy is the choice with the lowest price per unit (unit price).

Donna Kelsch is comparing dry cat food brands for her cats Nicki and Nasty. If Nicki and Nasty’s favorite, Funny Fish, comes in the three sizes listed below, which size is the best buy?

Hint: Determine the unit price for each size. Round to the nearest cent if necessary.

Size	Price	Unit Price
5 pounds	$12.25
10 pounds	$21.90
20 pounds	$38.50