Answer: 14 gallons of gas.
Step-by-step explanation: For the fractions, find a common denominator, which would be 10. To get 1/5 to have a denominator of 10, multiply each number by 2. You would get 2/10. 7 gallons fills his tank from 2/10 to 7/10. Subtract the two fractions.
7/10 - 2/10 = 5/10.
7 gallons filled his tank half way. We are trying to find the amount to fill his tank all the way. So multiply 7 by 2.
7 x 2 = 14
14 gallons of gas will fill his tank all the way.
I hope this helps!
