Warm-up: On page. Write
each ratio in
simplest form.
1.
2.
3.
4.
5.
48 : 12
36 to 9
75 to 15
42 : 7
125 to 5
Rates
What is rate?
• a ratio that compares two quantities
measured in different units.
• You have 2 buckets of ice cream for
11 people
2 buckets of ice cream/11 people
Example 1
You drive 180 mi in 3 hrs
180 mi/3 hrs
or 60 mi/hr
What is a unit rate?
HAS A DENOMINATOR OF 1!
Divide numerator by denominator!
Or you can reverse. The numerator
can be one instead. It depends on
how you set up your ratio.
Example 2: My heart beats
150 times in 2 minutes.
Rate:
150 heartbeats
2 minutes
Unit Rate (Divide to get it):
150 ÷ 2 = 75 heartbeats per minute.
75 heartbeats
=
1 minute
Example 3:
Find the Unit Rate
Amy can read 88 pages in 4 hours. What is the
unit rate? (How many pages can she read per
hour?)
88 pages
4 hours
22 pages / hour
=
22 pages
1 hour
Example 4:
Find the Unit Rate
A box of crackers has 420 calories in 6 servings.
Find the unit rate for 1 serving of crackers.
420 calories
6 servings
70 calories / serving
=
70 calories
1 serving
How do you compare
unit prices?
• Use division to find the unit prices
(rate) of both products.
• Smaller number (costs less) is the
better value.
Example 5
Juice is sold in two different sizes. A 48-fluid
ounce bottle costs $2.07. A 32-fluid ounce
bottle costs $1.64. Which is the better buy?
$2.07
48 fl.oz.
$1.64
32 fl.oz.
0.043125
0.05125
$0.04 per fl.oz.
$0.05 per fl.oz.
The 48 fl.oz. bottle is the better value because it is $0.01 less per fluid ounce.
Example 6
You can buy 3 bagels for $2.85 or 5 bagels for
$4.00. Which is the better buy?
$2.85
3 bagels
$4.00
5 bagels
$0.95 / 1 bagel
$0.80 / 1 bagel
The 5 bagels are the better value because it costs $0.15 less per bagel.