Answer: 14
==============================
Step-by-step explanation:
We can loosely use the equal sign to connect the two ideas of "278.2 miles" and "19.6 gallons" like so
278.2 miles = 19.6 gallons
basically saying that it takes 19.6 gallons of gas to drive 278.2 miles
--------
We want to know how many miles Jack can drive on 1 single gallon of gas. So we want to turn the "19.6 gallons" into "1 gallon".
To do this, we divide both sides of that equation mentioned by 19.6
--------
278.2 miles = 19.6 gallons
(278.2/19.6) miles = (19.6/19.6) gallons
14.1938775510204 miles = 1 gallon
14 miles = 1 gallon
Jack's car has a mile per gallon (mpg) rating of 14 mpg. This means he can travel 14 miles for each gallon of gas used up.
--------
In short, you simply divide 278.2 over 19.6 and then round to the nearest whole number to get your final answer of 14.