48 is the average speed
he uses 7.3 dollars per hour
6.6 per mile
21.7 gallons per mile
3.20 dollars per gallon of gas
these are the answers I could get
 
        
             
        
        
        
Yes, 14 is correct.
15: 3^4 - 4
16: 7n - 6
17: n^2 / 8
18: 3n x 9
        
             
        
        
        
Forty two plus sixty three that's your answer