Answer:
7.5 quarts
Explanation:
There are 4 quarts in a gallon, so 0.75 gallons is 3 quarts. Varnish is being used at the rate of ...
(3 quarts)/(10 doors) = 0.3 quarts/door
At that rate, the amount required for 25 doors is ...
(0.3 quarts/door)(25 doors) = 7.5 quarts
7.5 quarts are required for 25 doors.