For number 16 we need to write the data as a ratio then convert to a unit rate (amount per 1)...
308/14 = x/1
Cross multiply
14x = 308
x = 308/14
x = 22
So the fuel efficiency is
22 miles per 1 gallon or
22/1
For number 17, since the car was driven at 48 mph, we just have to divide distance driven by speed to get how long it took...
288 miles ÷ 48 mph =
6 hours