Linear Functions and Word Problems

Is the graph linear, exponential or neither?

• Linear

• Exponential

• Neither

A holiday meal costs $12.50 a person plus a delivery fee of $30.  Which equation represents the amount a holiday meal costs, including delivery, for x people?

• y = 30 + 12.5x 

• y = 12.5 + 30

• y = 12.5 + 30x

Easy Car Rental charges $8.50 an hour plus a rental fee of $25.50. Which equation represents the total charges for x hours?

• y = 8.5 + 25.5

• y = 25.5 + 8.5x

• y = 8.5 + 25.5x

Sandra has a $20 itunes gift card and spends $3 each month.  Which equation can be used to find how much money Sandra has on her giftcard after x months?

• y = 3x + 20

• y = 3 + 20x

• y = -3x + 20

• y = -20x + 3

Which equation shows the number of bottles left after x days?
A family buys a case of water with 48 bottles and drinks 5 bottles per day.

• y = 48x + 5

• y = -5 + 48x

• y = -5x - 48

• y = 48 - 5x

Which of the following situations could be descried by the equation y= -25x + 120

• There are 120 people in the football stadium, and 25 more are entering each hour.

• A plumber charges $25 for a house call and $120 per hour.

• A teacher has 120 students. Her third period has 25 students

• There are 120 gallons of water in a tank. It releases water at a rate of 25 gallons per minute

Bob has $150 in his savings account and saves $40 per month.

• y = 150 + 40

• y = 40x + 150

• y = 150x + 40

The total cost (y) at an amusement park can be modeled by y=1.5x+20 where x is the number of rides you ride. What is the price per ride?

• 1.5

• 21.5

• 0

• 20

The Roaming Cell Phone Company charges $15.00 per month plus $0.20 per minute of airtime usage.  If Juanita uses x minutes of airtime, what is an equation that can be used to determine her monthly cell phone bill (C)?

• C = 0.20x + 15

• C =15 (0.20x)

• C = 15 + x + 0.20

• C = 0.20 + 15x

Sonya has $40 in her lunch account and pays $2 each day to eat lunch.  Which equation can be used to find the amount of money Sonya has left on her account after x days?

• y = 40 + 2x

• y = 40 - 2x

• y = 2 + 40x

• y = 2 - 40x