Understanding Ratios and Proportions

Preschool Teacher-Student Ratio

• A preschool has a 2:5 teacher to student ratio
• Last year, there were 40 teachers and 16 students (total 56)
• This year, there are 50 teachers and 20 students (total 70)
• Other possible teacher/student ratios were presented, with varying totals of teachers and students.

Tile Ratio for Patio Design

• Jose uses 12 brown tiles and 8 white tiles for a patio section.
• The ratio of brown tiles to total tiles is 12:20, which simplifies to 3:5.

Senator Party Affiliation

• The 109th Congress had 100 senators.
• The ratio of Republicans to Democrats was 5:4
• There were 55 Republican senators and 44 Democratic senators.
• There was 1 Independent senator.

Animal Shelter Ratio

• An animal shelter has a 9:7 ratio of cats to dogs.
• The ratio of dogs to all animals is 7:16.
• A different shelter has a 6:5 ratio of cats to dogs.
• If both shelters have 18 cats, the second shelter has more dogs.

Ratio Table and Coordinate Plane

• A ratio table with X and Y values is given.
• The pairs in the table are plotted on a coordinate plane.

Cars Passing Intersection

• 32 cars pass through an intersection per hour.
• In 5.25 hours, 168 cars pass through the intersection.

Better Banana Buy

• Jessica can buy 10 pounds of bananas for $14.90 or 8 pounds for $12.08.
• The better buy is 10 pounds for $14.90, because it's cheaper per pound.

Marie's Chapter Writing

• Marie has 8 hours to write a 45-page chapter.
• She writes at a constant rate of 4 pages per hour.
• She can write 32 pages in 8 hours, which is not enough to complete the chapter.

Mile Walking Comparison

• Jenna walks 12 miles in 5 days (2.4 miles per day).
• Alex walks 7 miles in 3 days (2.33 miles per day).
• Jenna walks more miles per day.

Team Fundraising

• The soccer team raised $300.
• The lacrosse team raised $450.
• The lacrosse team raised $1.50 for every $1 dollar raised by the soccer team.

Class Play Ratio

• Mr. Flynn's class has 28 students.
• The ratio of students in the play to those not in the play is 2:5.
• There are 8 students in the play.

Bicycle Riding Comparison

• Kristy rides 6 miles in 40 minutes.
• Jax rides 4 miles in 30 minutes.
• Kristy's rate is better because she takes fewer minutes to travel the same distance.

Shampoo and Conditioner Ratio

• A hair salon uses 4 bottles of shampoo for every 3 bottles of conditioner.
• A graph shows the ratio.
• 16 bottles of shampoo corresponds to 12 bottles of conditioner.