Answer:
A car is more fuel efficient and it goes 30 miles per gallon (5/12 gallon to travel 12 1/2 miles)
Explanation:
A car : 5/12 gallon to travel 12 1/2 miles
(12 1/2) / (5/12) =
(25/2) / (5/12) =
25/2 * 12/5 =
150/5 =
30 miles per gallon
B car : 5/7 gallon to travel 20 5/7 miles
(20 5/7) / (5/7) =
(145/7) / (5/7) =
145/7 * 7/5 =
145/5 =
29 miles per gallon
most fuel efficient is A car....it gets 30 miles per gallon