Slope-intercept from word problems

 In order to join an online learning community, there is a $20 startup fee and a $5 charge each month. Write an equation in slope-intercept form that models this situation.

• y = 20x + 5
• y = 5x +20

Suppose that a bike rents for $4 plus $1.50 per hour. Write an equation in slope-intercept form that models this situation.

• y = 4x + 1.50
• y = 1.50x + 4

Suppose that a bike rents for $4 plus $1.50 per hour. Write an equation in slope-intercept form that models this situation.  After how many hours will the bike rental cost a total of $10?

• 4 hours
• 3 hours
• 2 hours 
• 1 hour

An airplane 30,000 feet above the ground begins descending at a rate of 2,000 feet per minute.  Write an equation

• y=-2000x+30000
• y=-30000x+2000
• y=2000x-30000
• y=-2000x-30000

An airplane 30,000 feet above the ground begins descending at a rate of 2,000 feet per minute.  Use your equation to find the altitude of the plane after 5 minutes.

• 20,000 feet after 5 minutes
• 40,000 feet after 5 minutes
• 148,000 feet after 5 minutes

Suppose that the water level of a river is 34 feet and that it is receding at a rate of 0.5 foot per day. Write an equation for the water level, L, after d days. 

• L = 34 - 0.5d
• L = 34d - 0.5
• d = 34 - 0.5L

Suppose that the water level of a river is 34 feet and that it is receding at a rate of 0.5 foot per day. Write an equation for the water level, L, after d days. In how many days will the water level be 26 feet?

• 16 days
• 15 days
• 10 days
• 9 days

For babysitting, Nicole charges a flat fee of $3, plus $5 per hour. Write an equation for the cost, C, after h hours of babysitting. 

• C = 5h + 3
• C = 3h + 5
• H = 5c + 3
• H = 3c + 5

For babysitting, Nicole charges a flat fee of $3, plus $5 per hour. Write an equation for the cost, C, after h hours of babysitting. How much money will she make if she baby-sits 5 hours?

• $28 in 5 hours
• $20 in 5 hours

A plumber charges $25 for a service call plus $50 per hour of service. Write an equation in slope-intercept form for the cost, C, after h hours of service. 

• C = 25 + 50h
• C = 50 + 25h
• H = 25 + 50c
• H = 50 + 25c