Lesson 6-2Rates

Students will be able to solve problems involving rates.

50 Miles1Hour

$252 HOURS

100 words2 minutes

Rate: A ratio that compares twoquantities with different kinds of units!

Simplify rates so the denominator is 1To simplify rates so the denominator is 1 just divide the numerator by the denominator.

100 ÷ 2 =

50So the unit rate of 100 words

2 minutesis50 WORDS1 MINUTE

÷÷

22

If the numerator is a decimal that’s okay!

Unit RatesUnit Rate: a rate that is simplified so that it hasa denominator of 1 unit!

Find the unit rate:24 mi

3h8 MI1 H

Read as 8 miles per 1 hour!

÷ 3÷3

COMMON UNIT RATESFOUND ON PAGE 287 IN YOUR BOOK!

Rate Unit Rate Abbreviation Name

Number of miles 1 hour

Miles per hour

Mi/h or mph Average speed

Number of miles 1 gallon

Miles per gallon

Mi/gal or mpg Gas Mileage

Number of dollars 1 pound

Price per pound

Dollars/lb or $/lb.

Unit Price

Number of dollars 1 hour

Dollars per hour

Dollars/hr or $/hr

Hourly wage When determining units rates involving Dollars it is generally more helpful to find dollars/ unit!

WHICH IS A BETTER BUY?Amount Total cost

16 oz Orange Juice $1.28

64 oz Orange Juice $2.56

To find the lowest price, find and compare the unit price for each container.

How do we set it up as a rate? 16oz OR $1.28 $1.28 16 oz

$1.28 $2.56 16 oz 64 oz

How do we find the unit rates? Just divide numerator by denominator

Divide the numerator by the denominator!

WHICH IS A BETTER BUY CONTINUED!$1.2816 oz 1.2816

.0 0 8

−128

000

So, the unit price of the 16 oz container is: $.08/oz

$2.5664 oz

2.5664.0 0 4

─256000

What is the unit rate for the 64 oz container? $.04/OZ

Which is a better buy?

Kyle ate 12 hot wings in 4 minutes at Wild Buffalo Wings. At this rate how many wings can he eat in 7 minutes?

First find the unit rate!

12 WINGS 4 MINUTES

÷ 4= ÷ 4=

3 WINGS1 MINUTE

Now we know that Kyle can eat 3 wings per minute, so how many can he eat in 7 minutes?What do you do?

Multiply the unit rate by 7 minutes!3 WINGS1 MINUTE x 7 minutes = 21 WINGS

Divide out the common units! Kyle can eat 21 wings in 7 minutes!

Homework Time:

Pgs. 289-290Pblms. 1-14 all, & 22