LearnAlgebra foundationsProportions and Linear Relationships

1 Proportions

1.1 Exercises

1.1.1 Problem set

For each of the following problems, identify also if the relationship between the independent and dependent quantities is a proportion.

  1. Say, you are doing a summer job. Your goal is to earn a certain amount of money so that you could buy a computer for yourself. What is a good independent quantity that the money you earn depends on?
  2. A pediatrician wants to understand a child’s growth by checking the height of the kid over time. What is the independent quantity that the dependent quantity height relates to?
  3. A family is planning a vacation to Orlando, and is estimating how much it costs them for hotel stay on the trip. What is a good independent quantity that the cost could be related to?
  4. A paving company is estimating the time it would take to pave a street. What is a good independent quantity that time it takes to pave could be related to?
  5. A city council is making certain plans for the city development based on how the population of the city grew over time in the past. What is a good independent quantity that population of the city could be related to?

1.1.2 Problem set

For each of the following problems, determine the independent quantity based on the question asked. Then, explain the meaning of unit rate in the problem’s context and find the value of the unit rate.

  1. 12 men are able to paint 3900 square feet of walls in a day. How many men are required to paint 900 square feet of walls in a day?
  2. To pave a 5600m long road in a day, it takes 24 machines. How many machines does it take to pave a 11900m long road in the same amount of time?
  3. 8 backpacks cost \$25.00. How many backpacks could I buy with \$40.00?
  4. During a hurricane relief, 33 tonnes of grain were required to support an affected neighborhood with 18000 families. How many tonnes of grain are required to support a neighborhood of 42000 families?
  5. 16 high school students are able to arrange books in 30 bookshelves in one hour. How many bookshelves can 30 students arrange in one hour?
  6. A landlord makes \$33000 per year by renting out 21 condo units.
    1. How much money will he make per year if he rents out 49 condo units?
    2. If he needs to make at least \$40000 per year, how many condos must he rent out?
  7. A car drives 121 miles on 5.5 gallons of gas.
    1. How many miles can be driven on 7.5 gallons of gas?
    2. How many gallons of gas are required to drive 198 miles?

1.1.3 Problem set

  1. 16 high school students are able to arrange books in a library in 5 hours. How many hours do 28 students need to arrange the library books?
  2. A service organization stores food in their pantry . It estimates if the pantry is full, the food in there is sufficient to feed 36 people for 6 days. At one particular time, the organization is required to house 42 people. How many days would the food (from the pantry that is full) last feeding all the 42 people?
  3. It takes 24 machines 5 days to pave a road. How many machines are required to pave a similar road in 3 days?
  4. It takes 5 days for 8 painters to paint the interior of a house. How many days would it take for 12 painters to paint the interior of a similar house?

1.1.4 Problem set

  1. A car going at 40 mph is able to cover a certain distance in 45 minutes. How much time will a car going at 72 mph take to cover twice that distance?
  2. Sam runs at 8mph, while Jack runs at 6mph. They both are running along the same loop in a park. What is the proportion of time taken by Sam to the time taken by Jack?

1.1.5 Problem set

  1. It takes 24 machines 5 days to pave a 5600m long road. How many machines does it take to pave a 12600m long road in 6 days?
  2. It takes 4 men 6 days to paint a 100 sq. ft wall. How many sq.ft of the wall can 3 men paint in 10 days?
  3. It takes 4 men 6 days to paint a 100 sq. ft wall. How many days will it take 6 men to paint 75 sq. ft. wall?
  4. It takes 36 men 7 days to plant seeds in a 600 sq. ft. field. How many days does it take for 63 men to plant seeds in a 900 sq. ft. field?
  5. Marvin can mow a yard in 5 hours. If Marvin and Tim work together, they can finish the mow in 3 hours. If Tim works by himself, how long would it take for Tim to mow the yard?

2 Linear relationships

2.1 Exercises

2.1.1 Problem set