Linear Word Problems

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

The local service center advertises that it charges a flat fee of $50 plus $8 per mile to tow a vehicle. Write an equation that represents the total cost (C) of a service for m miles of towing.

• C = 50m +8

• y = 50x + 8

• C = 8m + 50

A fitness club opens with 80 members. Each month the membership increases by 15 members. Which equation represents the relationship between the number of months the club has been opened, x, and the total fitness club membership, y?

• y=15x
• y=15x+80
• y=x+15
• y=80x+15

Speedy Boat Rental charges a $15 deposit fee plus $2 for each hour of use to rent a paddle boat.  Write an equation for C, the total cost, to rent the boat for h hours.

• C = 15h + 2

• h = 15C + 2

• C = 2h + 15

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

A man is climbing down from 100 feet high descending 30 feet per minute.

• y = - 30x + 100

• y = 100 + 30x

• y = 100x + 30

• y = 100x - 30

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 = 15 + 0.20x

• C =15 (0.20x)

• C = 15 + x + 0.20

• C = 0.20 + 15x

Jenny went to the sale at Kohl's last weekend.  
T-shirts were on sale for $15 each and hoodies were on sale for $20 each.  If she spent $150 total, write an equation to represent this situation.  

• 20x + 15 = y 
• 35x = y 
• 15x + 20y = 150 
• 150 - 20x = 15y 

Write an linear equation to model the following:
You want to buy desserts, ice-cream is $2.50 per scoop and puppychow is $4 per bag and you want to spend $20. 

• y=2.50x+4
• 2.50x+4y=20
• y=4x+2.5

In order to join a dancing club, there is a $30 startup fee and a $4 monthly fee. Write an equation in slope-intercept form that models this situation.  After how many months will the total cost be $58?

• 7 months
• 6 months
• 5 months 
• 4 months