Unit Rates and Proportions

Front

What is a unit rate?

Back

A unit rate is a comparison of two different quantities where one of the quantities is expressed as a quantity of one. For example, if a car travels 300 miles in 5 hours, the unit rate is 60 miles per hour.

Front

How do you find a unit rate from a ratio?

Back

To find a unit rate from a ratio, divide the first quantity by the second quantity to express it as a quantity of one. For example, if the ratio is 10 apples for $5, the unit rate is $5/10 apples = $0.50 per apple.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if 1/2 = 2/4, then these two ratios are in proportion.

Front

How can you solve for a missing value in a proportion?

Back

To solve for a missing value in a proportion, cross-multiply the ratios and then solve the resulting equation. For example, if a/b = c/d, then ad = bc.

Front

If 3 pizzas feed 9 people, how many pizzas are needed for 36 people?

Back

12 pizzas are needed. (3 pizzas / 9 people) = (x pizzas / 36 people) leads to x = 12.

Front

What is the formula to calculate unit price?

Back

Unit price = Total price / Number of units. For example, if 5 ice cream bars cost $12.25, the unit price is $12.25 / 5 = $2.45 per ice cream bar.

Front

If a recipe requires 2 cups of flour for 4 servings, how much flour is needed for 10 servings?

Back

5 cups of flour are needed. (2 cups / 4 servings) = (x cups / 10 servings) leads to x = 5.

Front

What is the relationship between unit rates and proportions?

Back

Unit rates can be used to create proportions. If you know the unit rate, you can set up a proportion to find unknown quantities.

Front

How do you convert a ratio to a percentage?

Back

To convert a ratio to a percentage, divide the first number by the second number and then multiply by 100. For example, the ratio 1:4 is (1/4) * 100 = 25%.

Front

If 150 people wait 20 minutes for a ride, how long will 1200 people wait?

Back

160 minutes. The waiting time increases proportionally with the number of people.