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?
the tank was 1/6 full, and after 2 gallons, is 1/2 full
that means 1/2 - 1/6 = 1/3 of the tank was filled
x: total capacity of the tank
x/3 = 2
x = 6
