8th Rates, 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 1. It is often expressed as a quantity per one unit, such as miles per hour or dollars per item.

Front

How do you calculate a unit rate?

Back

To calculate a unit rate, divide the quantity of one item by the quantity of another item. For example, if you have 60 cookies made with 3 cups of flour, the unit rate of flour per cookie is 3 cups ÷ 60 cookies = 0.05 cups per cookie.

Front

What operation is primarily used to find unit rates?

Back

Division.

Front

If a car travels 150 miles in 3 hours, what is the unit rate in miles per hour?

Back

50 miles per hour.

Front

If a recipe requires 4 cups of sugar for 8 servings, how much sugar is needed for 1 serving?

Back

0.5 cups of sugar.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

Front

How can you determine if two ratios form a proportion?

Back

Cross-multiply the ratios. If the cross products are equal, then the ratios form a proportion.

Front

If 5 apples cost $2.50, what is the cost per apple?

Back

$0.50 per apple.

Front

When is it useful to calculate unit rates?

Back

It is useful to calculate unit rates when comparing prices or quantities to determine the best deal.

Front

If a car uses 12 gallons of gas to travel 300 miles, what is the unit rate in miles per gallon?

Back

25 miles per gallon.