Let's call the fuel consumption of the first car "x" and the second car "y"
x + y = 35 is the total fuel consumed.
20x + 25y = 775 is the distance traveled.
Solve the two equations. Skipping a few steps, I getÂ
5y = 75. Therefore y = 15. So y used 15 gallons of gas. Therefore x used 20 gallons.
20 gallons, 15 gallons.