Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply the terms and then isolate the variable.

Front

If a car travels 280 miles in 7 hours, what is its speed in miles per hour?

Back

Speed = Distance/Time = 280 miles / 7 hours = 40 miles per hour.

Front

If 7 sandwich rolls cost $1.68, what is the cost of one sandwich roll?

Back

Cost of one roll = Total cost / Number of rolls = $1.68 / 7 = $0.24.

Front

What is the formula for finding the missing value in a proportion?

Back

If a/b = c/d, then ad = bc.

Front

If 5 apples cost $2.50, how much do 20 apples cost?

Back

Cost of 20 apples = (20/5) * $2.50 = $10.00.

Front

What is the cross-multiplication method?

Back

Cross-multiplication involves multiplying the numerator of one ratio by the denominator of the other ratio.

Front

If a recipe requires 3 cups of flour for 4 servings, how much flour is needed for 10 servings?

Back

Flour needed = (10 servings / 4 servings) * 3 cups = 7.5 cups.

Front

What is a unit rate?

Back

A unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity per one unit.

Front

If a car travels 240 miles in 4 hours, how far will it travel in 10 hours at the same speed?

Back

Distance = Speed * Time; Speed = 240 miles / 4 hours = 60 miles/hour; Distance in 10 hours = 60 * 10 = 600 miles.