Transcript Document

Unit Rate
Review
Vocabulary Review
• A ratio is a comparison of two quantities by division.
̶
17 out of 20 students, or 17
20
• A rate is a special type of ratio comparing two
quantities with different units.
– Driving 120 miles in 2 hours, or 120 miles
2 hours
• A unit rate is a rate that is simplified so that it has a
denominator of 1 unit.
– Driving 120 miles in 2 hours, or 120 miles  60 miles
2 hours
1 hour
Example 1:
Andy biked 24 miles in 4 hours. If he
traveled at a constant speed, how many miles
did he ride in 1 hour?
Write a verbal model of
what you are comparing.
Substitute in the values
given for each quantity.
Since a unit rate has a
denominator of 1 unit,
divide the numerator and
denominator by 4.
miles
hours
24 miles
4 hours
24  4 6 miles

4  4 1 hour
Andy biked 6 miles per hour.
Example 2:
A 12-pack of Gatorade costs $13.44.
What is the unit price per bottle?
Write a verbal model of
what you are comparing.
Substitute in the values
given for each quantity.
Divide the numerator and
denominator by 12 to find
the unit rate.
cost
bottle
$13.44
12 bottles
$13.44  12 $1.12

12  12
1 bottle
The unit price is $1.12 per bottle.
Example 3:
The price of three different bags of
cat food are shown in the table to the right.
Which bag has the lowest price per pound?
Write a verbal model of
what you are comparing.
For the 3.5 lb bag,
For the 7 lb bag,
For the 20 lb bag,
price
pound
Cat Food Prices
Size of bag
Price
(lbs)
($)
3.5
4.83
7
9.45
20
27.20
$4.83  3.5 $1.38

3.5  3.5
1 lb
$9.45  7 $1.35

7 7
1 lb
$27.20  20 $1.36

20  20
1 lb
The 7 pound bag is the least expensive at $1.35 per pound
Example 4:
After 3.5 hours, Peyton had traveled 161miles. If she travels at
a constant speed, how far will she have traveled in 4 hours?
Write a verbal model of
what you are comparing.
Find the unit rate in
miles per hour.
miles
hours
161 miles  3.5 46 miles

3.5 hours  3.5 1 hour
Multiply the unit rate, or average speed,
by the number of hours traveled.
46 miles
(4 hours)  184 miles
1 hour
Peyton travels 184 miles in 4 hours.
Example 5:
Jerry can jog 1⅓ miles in ¼ hour. Find
his average speed in miles per hour.
Write a verbal model of
what you are comparing.
Substitute in the values
given for each quantity.
Since average speed in
miles per 1 hour, divide
the numerator and
denominator by ¼ .
miles
hour
1
1 miles
3
1
hour
4
1 1 4  4 miles
1
 
1 
5 miles
3 4  3 1 
 3
1 1
1 hour
1 hour

4 4
Jerry jogs at an average speed of 5 ⅓ miles per hour.
Example 6:
Mr. Isaacs is spreading mulch in his yard.
He spreads 4⅔ square yards in 2 hours. How
many square yards can he mulch in 1 hour?
Write a verbal model of
what you are comparing.
sq. yds.
hours
Substitute in the values
given for each quantity.
2
4 miles
3
2 hours
Divide the numerator and
denominator by 2 to find
the unit rate.
2 2 14  1 sq. yds.
1
 
4 
2 sq.yds.
3 1  3 2 
 3
22
1 hour
1 hour
Mr. Isaacs can mulch 2 ⅓ square yards per hour.