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 one unit. For example, if you travel 60 miles in 2 hours, the unit rate is 30 miles per hour.

Front

How do you calculate the unit price of an item?

Back

To calculate the unit price, divide the total price by the number of units. For example, if a pack of 10 slices of cheese costs $2.48, the unit price is $2.48 ÷ 10 = $0.248 per slice.

Front

If a car travels 150 miles on 5 gallons of gas, what is the unit rate of miles per gallon?

Back

30 miles per gallon.

Front

When is it useful to find a unit rate?

Back

It is useful to find a unit rate when comparing prices or rates to determine which option is better.

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

If a recipe calls for 2 cups of sugar for every 3 cups of flour, what is the ratio of sugar to flour?

Back

The ratio of sugar to flour is 2:3.

Front

How can you find the missing value in a proportion?

Back

You can find the missing value by cross-multiplying and solving for the unknown. For example, if a/b = c/x, then a*x = b*c.

Front

What is the unit price of Velveeta cheese slices if they cost $3.18 for 12 slices?

Back

$3.18 ÷ 12 = $0.265 per slice.

Front

If you buy 4 pounds of apples for $3.20, what is the cost per pound?

Back

$3.20 ÷ 4 = $0.80 per pound.

Front

What happens to the unit rate if the total quantity increases but the total price remains the same?

Back

The unit rate decreases because the cost is spread over more units.