The car's gas mileage, in miles per gallon, for the entire trip is 16.
Step-by-step explanation:
Car gets 12 miles per gallon uphill and 24 miles per gallon downhill.
Uphill mileage = 12 miles per gallon
Downhill mileage = 24 miles per gallon
Distance to peak = 48 miles.
Distance to peak = Uphill mileage x Gas used uphill
48 = 12 x Gas used uphill
Gas used uphill = 4 gallon
Distance to peak = Downhill mileage x Gas used downhill
48 = 24 x Gas used downhill
Gas used downhill = 2 gallon
Total distance traveled by car = 48 + 48 = 96 miles
Total gas used = 4 + 2 = 6 gallons
Total distance = Mileage x Gas used
96 = Mileage x 6
Mileage = 16 miles per gallon
The car's gas mileage, in miles per gallon, for the entire trip is 16.