Solving 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 two ratios and set the products equal to each other.

Front

If a car travels 120 miles in 3 hours, what is its speed in miles per hour?

Back

Speed = Distance / Time = 120 miles / 3 hours = 40 miles per hour.

Front

If 50 apples cost $25.00, what is the cost of one apple?

Back

Cost of one apple = Total cost / Number of apples = $25.00 / 50 = $0.50.

Front

How do you find the cost of 75 apples if 50 apples cost $25.00?

Back

Set up a proportion: 50 apples / $25.00 = 75 apples / x. Cross-multiply and solve for x.

Front

If Nora took 10 hours to walk 30 miles, how long would it take her to walk 9 miles?

Back

Time for 9 miles = (10 hours / 30 miles) * 9 miles = 3 hours.

Front

What is the unit rate?

Back

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

Front

If Mike takes 18 minutes to read 4 pages, how long does it take him to read 1 page?

Back

Time per page = 18 minutes / 4 pages = 4.5 minutes per page.

Front

How do you calculate the time to read 30 pages if you know the time for 1 page?

Back

Time for 30 pages = Time per page * 30 pages.

Front

If 13 candy bars weigh 26 ounces, what is the weight of one candy bar?

Back

Weight of one candy bar = Total weight / Number of candy bars = 26 ounces / 13 = 2 ounces.