Taxi charges

This task is about reading information from a graph.
graph of two taxi company charges
 
On Friday nights Shane catches a taxi home. The graph shows the prices charged by two different taxi companies - Black and Red Taxis and Express Taxis.
Use the graph to answer the questions that follow.
 
a)
If Shane had only $6.00, how far could be travelled if Black and Red Taxis were used? __________ km
 
b)
Which taxi company would be cheaper, and by how much, if Shane was travelling 8 kilometres?
 
____________________________ would be cheaper by $ _______________________
 
c) Point X on the graph is where the 2 lines cross. What does point X represent?
 

 
 
d)
Let C = "price charged" and k = "number of kilometres".
Complete an equation to show what each taxi company charges.
 
  i)   Express Taxis: C = ____________________
 
ii)  Black and Red Taxis: C = ____________________