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 440 miles in 8 hours, the unit rate is 55 miles per hour.

Front

How do you calculate a unit rate?

Back

To calculate a unit rate, divide the total quantity by the number of units. For example, if a car travels 440 miles in 8 hours, divide 440 by 8 to get 55 miles per hour.

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 do you solve a proportion?

Back

To solve a proportion, cross-multiply and then divide. For example, if 2/3 = x/6, cross-multiply to get 2*6 = 3*x, then solve for x.

Front

If one pizza feeds 3 people, how many pizzas are needed for 36 people?

Back

12 pizzas are needed because 36 divided by 3 equals 12.

Front

How do you find the total amount saved over a period of time using a unit rate?

Back

Multiply the unit rate by the number of time periods. For example, if Mary saves $17.50 in 3 weeks, in 15 weeks she will save $17.50/3 * 15 = $87.50.

Front

What is the relationship between dogs and cats if there are 5 dogs for every 20 cats?

Back

The relationship can be simplified to 1 dog for every 4 cats.

Front

How do you simplify a ratio?

Back

To simplify a ratio, divide both terms by their greatest common factor. For example, the ratio 5:20 can be simplified to 1:4.

Front

What is the formula for finding a unit rate?

Back

Unit Rate = Total Quantity / Number of Units.

Front

If a car travels 220 miles in 4 hours, what is the unit rate?

Back

The unit rate is 55 miles per hour (220 miles ÷ 4 hours).