Practice Ratio and Proportion

The class has 12 girls and 16 boys. What is the ratio of total students to boys? (simplest form)

In a certain apartment building, the ratio of tenants to cars is 3:5. If there are 30 tenants, how many cars are there?

Mathematical Equivalence

ON

In an animal shelter, the ratio of dogs to cats is 5 to 3. There are 25 dogs.  Write and solve a proportion to find the number of cats.

Mathematical Equivalence

ON

There were 5 ice cream cones for every 3 brownies sold at the ice cream shop. If there were 24 brownies sold, how many ice cream cones were sold?

Mathematical Equivalence

ON

A recipe calls for 2 cups of flour for every 3 cups of sugar. If you use 9 cups of sugar, how many cups of flour do you need?

• 4

• 6

• 8

• 10

If the ratio of cats to dogs is 3:4, how many cats are there if there are 20 dogs?

• 15 cats

• 25 cats

• 30 cats

• 10 cats

If the ratio of pencils to pens in a box is 7:5, how many pens are there if there are 21 pencils?

• 15

• 18

• 12

• 14

Answer explanation

To find the number of pens, set up fractions as an equality like this: 7/5 =21/x. 7*3 is 21, so multiply the 5 by 3 as well to get the number of pens, 15.

If the ratio of boys to girls in a class is 5:6 and there are 30 girls, how many boys are there?

• 25

• 20

• 24

• 28

If the ratio of red balls to blue balls in a bag is 5:3, how many blue balls are there if there are 20 red balls?

• 12

• 15

• 8

• 10

Answer explanation

If the ratio of red balls to blue balls is 5:3, and there are 20 red balls, set up an equality like this: 5/3 = 20/x. To get from 5 in the left numerator to 20 in the right numerator, multiply 5*4. Since the numerator is multiplied by 4, the denominator would also be multiplied by 4. 3*4 = 12.

If the ratio of cats to dogs in a pet store is 3:4, and there are 12 cats, how many dogs are there?

• 16

• 14

• 18

• 20