Slope and Intercept: Real-World Cost Challenges for 8th Graders

A car rental company charges a flat fee of $20 plus $0.15 per mile driven. Write the equation in slope-intercept form that represents the total cost (C) as a function of miles driven (m).

• C = 20m + 0.15

• C = 20 + 0.15m^2

• C = 0.15m + 20

• C = 0.15m - 20

A skateboard park charges an entrance fee of $5 and an additional $2 for each hour spent in the park. What is the slope and y-intercept of the equation that represents the total cost (C) for h hours?

• Slope: 2, Y-intercept: 5

• Slope: 5, Y-intercept: 2

• Slope: 2, Y-intercept: 0

• Slope: 0, Y-intercept: 5

A cell phone plan costs $30 per month plus $0.10 for each text message sent. Identify the slope and y-intercept of the equation that models the total monthly cost (C) based on the number of text messages (t).

• Slope: 0.05, Y-intercept: 25

• Slope: 0.10, Y-intercept: 20

• Slope: 0.15, Y-intercept: 30

• Slope: 0.10, Y-intercept: 30

A local gym has a membership fee of $50 and charges $10 per class attended. Write the equation in slope-intercept form for the total cost (C) based on the number of classes (c) attended. What is the slope?

• The slope is 5.

• The slope is 15.

• The slope is 20.

• The slope is 10.

A delivery service charges a base fee of $15 plus $2 for each mile driven. If the graph of the cost versus miles is plotted, what is the slope and y-intercept?

• Slope: 2, Y-intercept: 15

• Slope: 2, Y-intercept: 0

• Slope: 0, Y-intercept: 15

• Slope: 15, Y-intercept: 2

A farmer sells apples for $3 per pound and has a fixed cost of $10 for packaging. Write the equation in slope-intercept form that represents the total revenue (R) based on the pounds of apples sold (p).

• R = 3p + 10

• R = 10 + 3p

• R = 3p

• R = 5p

A taxi company charges a flat rate of $2.50 plus $1.50 per mile. If you graph the total fare (F) against the miles traveled (m), what is the slope and y-intercept?

• Slope: 1.50, Y-intercept: 3.00

• Slope: 1.50, Y-intercept: 2.50

• Slope: 2.50, Y-intercept: 1.50

• Slope: 1.00, Y-intercept: 2.50

A subscription service charges $12 per month with an initial sign-up fee of $24. Write the equation in slope-intercept form for the total cost (C) based on the number of months (m) subscribed. What does the slope represent?

• C = 12m; the slope represents the total cost without the sign-up fee.

• C = 10m + 24; the slope represents a discount of $10.

• C = 12m + 24; the slope represents the monthly cost of $12.

• C = 24m + 12; the slope represents the initial sign-up fee.

A concert ticket costs $50 and an additional $5 for each additional person. Write the equation in slope-intercept form for the total cost (C) based on the number of additional people (p). What is the slope?

• $50

• 5

• 10

• 3

A bike rental shop charges a one-time fee of $10 and $3 for each hour rented. If you were to graph the total cost (C) against hours rented (h), what would be the slope and y-intercept?

• Slope: 3, Y-intercept: 5

• Slope: 5, Y-intercept: 10

• Slope: 3, Y-intercept: 10

• Slope: 10, Y-intercept: 3