Unit Rates

Created by:

Mrs. Dube

Rate – a ratio that compares two quantities measured in different unitsEx. miles/per hour

Unit rate – a rate whose denominator is 1 when it is written as a fraction

First, make sure the ratio is written as a fraction

Next, divide the numerator and denominator by the denominator so your denominator will now be 1Ex. A woman exercises and her heart beats

835 times in 5 minutes. Write the ratio as a fraction 835/5 Now, divide by the numerator and denominator

by the denominator(835 beats/5minutes) ÷ 5/5 = 167/1

So the woman’s heart beats 167 times in 1 minute

To make 6 dozen cookies, you need 3 cups of flour; how many cups of flour are needed to make one dozen cookies?Write the ratio as a fraction: 3 cups/6 dozenNow, divide numerator and denominator by

the denominator: (3/6) ÷6/6 = .5/1 = .5You need .5 or ½ cup of flour to make one

dozen cookies

A recipe for 6 blueberry muffins calls for 360 grams of flour. How many grams of flour are needed to make each muffin?Write the ratio as a fraction: 360/6 Now, divide the numerator and

denominator by the denominator (360/6) ÷ 6/6 = 60/6

Each muffin requires 60 grams of flour

A recipe for cookies calls for 3 cups of brown sugar for 6 dozen cookies? How much brown sugar is need for one dozen cookies?First, write the ratio as a fraction:

Follow the same procedure to find the average speed Ex. A family travels 198 miles in 3 hours.

What is their average speed of travel? Write the ratio as a fraction: 198/3 Divide the numerator and denominator by the

denominator: (198/3) ÷ 3/3 = 66/1 The family travels an average speed of 66 miles

per hour

A airplane traveled 2,748 miles in 6 hours. What was the plane’s average rate of speed in miles per hour?First, write the ratio as a fraction:

Comparing different rates by finding the unit priceEx. A 32 oz. container of orange juice costs

$1.99, but a 64 oz. container costs $3.99 and a 96 oz. container costs $5.85. Which container offers the best value? First, write each container as a ratio and then

divide each ratio by its denominator to find the unit rate or unit price1.99/323.99/645.85/96

Next, divide each ratio by its denominator to find the price of one ounce

(1.99/32) ÷ 32/32(3.99/64) ÷ 64/64(5.85/96) ÷ 96/96

Now compare the prices for one ounce and determine which price is the best value

A 10 oz. bag of M&Ms costs $2.19, a 16 oz. bag costs $3.38, and a 28 oz. bag costs $5.49; which bag of M&Ms is the best value for the money?