Using Ratio Tables(Part 1: Creating equivalent ratios by adding on)

Definition

A ratio table is a tool used to organize equivalent ratios.

Example A

You can walk 6 miles in 2 hours. Make a table of equivalent ratios to show how far you can walk in 4 hours, 6 hours, 8 hours, and 10 hours.

Example A - ratio of 2 hours: 6 miles

Time in Hours

Distance in Miles

Example BJuan can read 9 pages in hisbook in 10 minutes. Make atable of equivalent ratiosto find how many pages hecan read in 20 minutes,

30 minutes, 40 minutes, 50 minutes, and 60 minutes.

Example B – ratio 9 pages: 10 minutes

Number of Pages

Time (in minutes)

Using Ratio Tables(Part 2: Creating equivalent ratios by multiplying)

A party planner said that 3 pizzas will serve about 7 people.

How many pizzas are needed for 350 people?

Example

# of Pizzas

# of People

3 7

Strategy #1

# of Pizzas

# of People

3 7300 700

× 100

Strategy #1

× 100

# of Pizzas

# of People

3 7300 700150 350

× 100

÷ 2 ÷ 2

Strategy #1

× 100

# of Pizzas

# of People

3 7300 700150 350

× 100

÷ 2

Solution!

Strategy #1

÷ 2

× 100

# of Pizzas

# of People

3 7

Strategy #2

# of Pizzas

# of People

3 715 35

× 5× 5

Strategy #2

# of Pizzas

# of People

3 715 35

150 350

× 5

× 10

Strategy #2

× 5

× 10

# of Pizzas

# of People

3 715 35

150 350

× 5

× 10

Solution!

Strategy #2

× 5

× 10

Now it’s your turn! Use a ratio table to solve each problem.Example #1:

Six wheel rotations on a bike takes you 10 yards. How many wheel rotations will it take to go 45 yards?

Example #2:In a bag of blue and yellow candies, the ratio of blue candies to yellow candies is 3:5. If the bag contains 60 yellow candies, how many blue candies are there?

Example #3:

James can send 12 text messages in 8 minutes. At this same rate, how long will it take James to send 75 text messages?

Example #4:

At a local college, 2 out of every 8 seniors live in apartments. About how many of the 28 seniors are likely to live in apartments?

Example #5:

In a class, the ratio of boys to girls is 3 to 4. If there are 12 boys in the class, then how many girls are there?