Car maintenance

This task is about comparing the different costs of two garages.
Two garages charge for repairs in different ways.
  • Kakariki Garage charges a standard $40 for a first look, and then $30 per hour for servicing.
  • Honore's Garage charges $60 for the first look, and then $25 per hour for servicing.
a)   Complete the table below to work out the costs of each garage for the hours they work.

 
Garage Hours worked on the car
1st look 1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 7 hours
Kakariki $40 $70 $_____ $_____ $_____ $_____ $_____ $_____
Honore's $60 $85 $_____ $_____ $_____ $_____ $_____ $_____
 
b)
 
Use your results in the table above to draw and label a graph that shows the cost of using each garage over time (in hours). 
 
 
 Cost of work on the car by hours worked
 
empty graph
 

Key

  ––  Kakariki Garage

- - - Honore's Garage
c) Use the graph to help you explain when it's cheapest to use each garage.