Slope and Y-Intercept: Real-World Applications for 8th Graders

A car rental company charges a flat fee of $50 plus $0.20 per mile driven. What is the slope of the graph representing the total cost as a function of miles driven?

• $0.10

• 0.20

• $50

• $0.50

If a student starts with 10 points and earns 2 points for each assignment completed, what is the y-intercept of the graph showing total points as a function of assignments completed?

• 8

• 10

• 12

• 15

A gardener plants a tree that grows 3 inches per month. If the tree is 12 inches tall when planted, what does the slope represent in this scenario?

• The slope represents the growth rate of the tree, which is 3 inches per month.

• The slope shows the amount of water the tree needs each month.

• The slope represents the initial height of the tree, which is 12 inches.

• The slope indicates the total height of the tree after one year.

A phone plan costs $30 per month plus $0.10 per text message. What is the slope of the cost graph, and what does it represent?

• $0.05

• 0.30

• $30

• 0.10

A factory produces 100 units of a product in the first month and increases production by 20 units each subsequent month. What is the y-intercept of the production graph?

• 120

• 80

• 200

• 100

A bike rental service charges a one-time fee of $15 and $5 per hour. What does the slope of the cost graph indicate about the rental service?

• The slope indicates the hourly charge of $5 for the bike rental.

• The slope shows a discount for renting multiple bikes.

• The slope represents the total cost of renting a bike.

• The slope indicates a flat fee of $15 for the rental.

A student saves $5 each week starting with $20. What is the y-intercept of the savings graph, and what does it represent?

• 20

• 30

• 15

• 25

A water tank is filled at a rate of 10 liters per hour, starting from an empty tank. What is the slope of the graph representing the volume of water in the tank over time?

• 5 liters per hour

• 20 liters per hour

• 15 liters per hour

• 10 liters per hour

A subscription service charges $25 per month with no initial fee. What is the slope of the cost graph, and what does it signify?

• The slope of the cost graph is 25, signifying that the cost increases by $25 for each month.

• The slope of the cost graph is 50, meaning the cost increases by $50 each month.

• The slope of the cost graph is 25, but it signifies a decrease in cost by $25 each month.

• The slope of the cost graph is 0, indicating no change in cost over time.

A runner completes a race in 30 minutes, maintaining a steady pace of 4 minutes per kilometer. What does the slope of the distance-time graph represent?

• The total distance of the race.

• The time taken to complete each kilometer.

• The runner's heart rate during the race.

• The speed of the runner.