Proportions - Real world problems

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 solve for the unknown variable.

Front

If Joe runs 2 miles in 20 minutes, how do you find the time to run 5 miles?

Back

Set up a proportion: 2 miles/20 minutes = 5 miles/x minutes. Cross-multiply and solve for x.

Front

What is the ratio of boys to girls if there are 3 boys for every 1 girl?

Back

The ratio is 3:1.

Front

How do you calculate the total hours Nik played video games in 10 days if he plays 6 hours every 2 days?

Back

First, find how many 2-day periods are in 10 days (10/2 = 5). Then multiply 5 periods by 6 hours: 5 * 6 = 30 hours.

Front

If Aryon reads 4 books every 3 weeks, how do you find out how long it takes to read 20 books?

Back

Set up a proportion: 4 books/3 weeks = 20 books/x weeks. Cross-multiply and solve for x.

Front

How many weeks will it take Chris to save $40 if he saves $8 every 2 weeks?

Back

First, find how many 2-week periods are needed to save $40: $40/$8 = 5 periods. Then multiply by 2 weeks: 5 * 2 = 10 weeks.

Front

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

Back

The formula is a/b = c/d, where a, b, c, and d are the values in the proportion.

Front

What does it mean if two ratios are equivalent?

Back

It means that they represent the same relationship between quantities.

Front

How can you check if your answer to a proportion problem is correct?

Back

You can check by substituting your answer back into the original proportion to see if both sides are equal.