Final answer:
The relation for the number of miles Bill travels, y, in terms of how much gas it uses is y = 30x, where x is the number of gallons.
Step-by-step explanation:
The relation for the number of miles Bill travels, y, in terms of how much gas it uses is given by the equation y = 30x, where x is the number of gallons. This means that for every gallon of gas his car consumes, it can run 30 miles.