Answer:
4 miles per gallon of fuel.
Explanation:
The fuel efficiency of a car is given by the ratio of distance traveled by car to the volume of fuel used.
Now, given that Nate's car will go 20 miles on 5 gallons of fuel.
Therefore, the fuel efficiency of Nate's car will be given by the ratio
=
=
= 4 miles per gallon of fuel. (Answer)