Rates, Ratios, 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 3 CDs cost $41.91, the unit rate is the cost per CD.

Front

How do you find the unit rate from a total cost?

Back

To find the unit rate, divide the total cost by the number of items. For example, for 3 CDs costing $41.91, the unit rate is $41.91 ÷ 3 = $13.97 per CD.

Front

What is the formula to calculate average speed?

Back

Average speed is calculated using the formula: Average Speed = Total Distance ÷ Total Time.

Front

If Jenny drives 265 miles in 5 hours, what is her average speed?

Back

Average speed = 265 miles ÷ 5 hours = 53 mph.

Front

What is a ratio?

Back

A ratio is a relationship between two numbers indicating how many times the first number contains the second. For example, the ratio of 10 drums to 75 instruments is 10:75.

Front

How do you simplify a ratio?

Back

To simplify a ratio, divide both terms by their greatest common divisor (GCD). For example, the ratio 10:75 simplifies to 2:15.

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 check if two ratios form a proportion?

Back

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

Front

What is the unit rate for 5 soft drinks costing $3.25?

Back

Unit rate = $3.25 ÷ 5 = $0.65 per drink.

Front

How do you express a ratio as a fraction?

Back

To express a ratio as a fraction, write the first quantity as the numerator and the second quantity as the denominator. For example, the ratio 10:75 can be expressed as 10/75.