Basic Mathematics for College Students

Find the best buy based on unit price.

If a grocery store sells a 5-pound package of hamburger for $18.75, a consumer might

want to know what the hamburger costs per pound. When we find the cost of 1 pound

of the hamburger, we are finding aunit price.To find the unit price of an item, we begin

by comparing its price to the number of units.

Then we divide the price by the number of units.

The unit price of the hamburger is $3.75 per pound.

Other examples of unit prices are:

• $8.15 per ounce


• $200 per day


• $0.75 per foot

Unit Price

A unit priceis a rate that tells how much is paid for oneunit (or oneitem). It is

the quotient of price to the number of units.

Unit price =

When shopping, it is often difficult to determine the best buys because the items that

we purchase come in so many different sizes and brands. Comparison shopping can be

made easier by finding unit prices.The best buy is the item that has the lowest unit price.

price

number of units

3.75

5 18.75

Price

 Number of units

$18.75 

5 pounds

6

422 Chapter 5 Ratio, Proportion, and Measurement

Self Check 9

FULL-TIME JOBSJoan earns $436

per 40-hour week managing a

dress shop. Write this rate as a

unit rate. (Hint:Find her hourly

rate of pay.)

Now TryProblem 61

EXAMPLE (^9) Part-time Jobs A student earns $74 for working 8 hours
in a bookstore. Write this rate as a unit rate. (Hint:Find his hourly rate of pay.)
StrategyWe will translate the rate from its given form in words to fractional
form. Then we will perform the indicated division.
WHYTo write a rate as a unit rate, we divide the numerator of the rate by the
denominator.
Solution
$74 forworking 8 hours can be written as.
To find the rate of pay for 1 hour of work (the unit rate), we divide 74 by 8.
Write a decimal point and two additional zeros to the right of 4.
The unit rate of pay is 1 hour$9.25 , which can be written as $9.25 per hour or $9.25/hr.

9.25

8 74.00

 72

20

 16

40

 40

0



$74

8 hours