Answer:
20 gallons!~
Step-by-step explanation:
Dad's car holds 20 gallons of gas because 50% of 14 is 7. Therefore, add 50% (or add 7 gallons of gas) mom's total amount of gas her car hold in order to Dad's.
So, 7 + 14 = 20, therefore giving your your answer of 20 gallons.
Hope this helps!~ <3