Answer: Last option is correct.
Step-by-step explanation:
Since we have given that
Amount of average of miles on each gallon of gas = 18
Let the number of miles be m
According to question, it becomes
Number of miles= Average of miles × Number of gallons of gas
[tex]m=18g\\\\\text{where g is the number of gallons of gas}[/tex]
Hence, Last option is correct.