Answer:
36 Quarts
Explanation:
Let the volume of the Aquarium be x quarts.
Hence amount of water filled in it will be
quarts
Also problem says that the tank is tilted until water level coincides with one edge of the bottom. At this position , the amount of water filled in the tank will be half of the total volume , as the slant water level will be the diagonal of the tank and a diagonal divides the tank in two halves.
Hence current volume of water in the tank will be

And in this process the amount of water poured out is 6 quarts. It will the difference between the amount of water earlier in the tank and the amount of water in the tank now. Hence



Hence the volume of the tank is 36 quarts.