Ratios and Rates
Which is the better buy?
$7.93 on a 15.25 ounce bag of potato chips
$11.75 on a 25-ounce bag of Doritos
25 oz. bag of Doritos
n/10 = 28/8
35
2 equal ratios form a __________
proportion
Which is the better buy?
12 car washes for $100
5 car washes for $45?
12 car washes
Solve the proportion: 25/20 = 45/x
36
This is the amount for one of something, such as the cost for 1 item.
unit rate
Find the unit rate: 51 floors in 3 buildings.
What is 17 floors per building.
Which is the better buy?
12 oz. Coca-Cola for $1.25
20 oz. Root Beer for $1.25?
20 oz. bottle of Root Beer
Solve the proportion: 4/h = 12/24
8
A comparison of two quantities
ratio
Find the unit rate for 9 slices for 3 people.
3 slices per person
Which is the better buy?
10 pencils for $2.40
32 pencils for $7.00?
32 pencils
A person who weighs 120 pounds on Earth weighs 20 pounds on the Moon. How much does a 93-pound person weigh on the Moon?
What is 15.5 lbs.
A ratio of two quantities with different units
rate
Find the unit rate for 36 apples for 6 baskets
6 apples for 1 basket.
Which is the better buy?
A dozen (12 bagels) for $7.80
1 pack of 3 bagels for $2.10?
1 pack of 3 bagels
A school requires 5 computers for every 20 students. Write a proportion that gives the number (c) of computers needed for 360 students.
What is 5/20 = c/360, c = 90 computers
You can buy six cans of soda for $2.50. How many cans of root beer can you buy for $10?
24 cans
In the proportion, a/b = c/d = the products a • d and b • c are called
cross products