Function Modeling Word Problems

A babysitter’s earnings e are a function of the number of hours n worked at a rate of $7.25 per hour.

• e = 7.25-n

• e = 7.25n

The price p of an ice cream is $3.95 plus $0.85 for each topping t on the ice cream.

• p = 0.85t - 3.95

• p = 0.85t + 3.95

• p = 3.95t + 0.85

A football team averages 4.5 yards/play. They start a drive on their own 20 yard line. Write a function that tells how far d from their own goal line they will be as a function of plays p.

• d= 4.5p - 20

• p=4.5d + 20

• p= 4.5d - 20

• d= 4.5p + 20

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. What will be the total cost for 8 hours of work?

• C = 50h + 25

• 25 = 5h + 50

• 90

• 425

Rufus collected 100 pounds of aluminum cans to recycle. He plans to collect an additional 25 pounds each week. Write the equation for the total pounds, P, of aluminum cans after w weeks. How long will it take Rufus to collect 400 pounds of cans?

• P = 100w + 25

• 12

• 20

• P = 25w + 100

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?

• H = 3c + 5

• C = 5h + 3

• 20

• 28

A canoe rental service charges a $20 transportation fee and $30 dollars an hour to rent a canoe. Write an equation representing the cost, y, of renting a canoe for x hours. What is the cost of renting the canoe for 6 hours?

• 200

• y= 30x + 20

• x + 30y -20

• 160

A water tank already contains 55 gallons of water when Baxter begins to fill it. Water flows into the tank at a rate of 8 gallons per minute. Write a linear equation to model this situation. Find the volume of water in the tank 25 minutes after Baxter begins filling the tank.

• 255

• y = 8x + 55

• 1383

• y = 55x + 8

A taxicab charges $4.25 for a ride and $1.50 per mile. Write a rule for describing the total rate r as a function of the total miles m. What is the taxi rate for 12 miles?

• 22.25

• r = 4.25m + 1.50

• 52.50

• r = 1.50m + 4.25

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?

• L = 500d - 34

• -16

• 12

• L = -1/2d + 34