An aquarium tank is 1/6 full of water. When 2 gallons of water are added, the tank becomes 1/2 full. What is the total capacity of the aquarium tank, in gallons?

Full Tank ==T

1/2T - 1/6T ==1/3T

1/3T ==2

T ==2 x 3 ==6 gallon - capacity of the full tank.