6th Grade: Module 1 Lesson 5

Solving Problems by Finding Equivalent

Ratios

Classwork: Example 1A County Superintendent of Highways is interested in the number of different types of vehicles that regularly travel within his county. In the month of August, a total of 192 registrations were purchased for passenger cars and pickup trucks at the local Department of Motor Vehicles (DMV). The DMV reports that in the month of August, for every 5 passenger cars registered, there were 7 pickup trucks registered. How many of each type of vehicle were registered in the county in the month of August?

Example 1(a)

Using the information in the problem, write four ratios and describe the meaning of each.

Example 1

Answer 5:7 part-to-part7:5 part-

to-part5 to 12 part-to-

whole7 to 12 part-to-

whole

Example 1(b)

Make a tape-diagram that represents the quantities in the ratios that you wrote.

Example 1(b) Tape Diagram

Passenger Cars

Pickup Trucks

Example 1(c)

How many equal-sized parts does the tape diagram consist of?

Example 1(c)

How many equal-sized parts does the tape diagram consist of?There are 12 equal-sized parts on this tape diagram.

Example 1(d)

What total quantity does the tape diagram represent?

Example 1(d)

What total quantity does the tape diagram represent?The total quantity the tape diagram represents is 192 vehicles.

Example 1(e)

What value does each individual part of the tape diagram represent?

Example 1(e)

What value does each individual part of the tape diagram represent?Divide the total quantity into 12 equal-sized parts.

Example 1(e)What value does each individual part of the tape diagram represent?Divide the total quantity into 12 equal-sized parts.192 ÷ 12 = 16

Example 2

The Superintendent of Highways is further interested in the number of commercial vehicles that frequently use the county’s highways. He obtains information from the Department of Motor Vehicles for the month of September and finds that for every 14 non-commercial vehicles, there were 5 commercial vehicles. If there were 108 more non-commercial vehicles than commercial vehicles, how many of each type of vehicle frequently use the county’s highways during the month of September?

Example 2 (Tape Diagram)

Non-Commercial Vehicles

Commercial Vehicles

Example 2 (Tape Diagram)

Non-Commercial Vehicles

These 9 sections represent the “more than

commercial vehicles,” which is 108. To determine how many cars each section

represents, divide 108 by 9 to get 12. Each

Commercial Vehicles section of tape diagram represents 12 vehicles.

Exercises (1)

Smartphone

Flip Phone

Exercises (1)

Smartphone

This section represents

500 more people who

own a smartphone.

Flip Phone

Exercise 2

Sammy

David

Exercise 2Sammy and David

Together they sold 160 water bottles. How many did each boy sell?

Exercise 3

Mr. Johnson

Ms. Siple

Exercise 3Mr. Johnson andMs. Siple

Mr. Johnson and Ms. Siple folded a total of 300 report cards. How many did each person fold?

Exercise 4

Boys

Girls

Exercise 4

Boys

Girls

These 5 sections represent the “250 more girls

than boys,” which is 250. How do you determine how many girls each section represents?

ClosingHow do tape diagrams help solve ratio word problems?

Tape diagrams help find an equivalent ratio when given the part-to-part ratio and the total of those two quantities. Tape diagrams help find an equivalent ratio when given the part-to-part ratio and the difference between those two quantities.

Exit Ticket

When Carla looked out at the school parking lot, she noticed that for every 2 minivans, there were 5 other types of vehicles. If there are 161 vehicles in the parking lot, how many of them are not minivans?