Arectangular tank with a square base is 1/4 full of water the side lengths of the square bases 20 inches one another 3000 cubic inches of the water is poured into the tank it becomes 2/3 full find the capacity of the tank

1/4 to 2/3

2/3-1/4=8/12-3/12=5/12
so the change is 5/12

the volume of the tank and dimentions are irrelivant for now

so

3000 cubic inches was added and that was a change of 5/12

5/12 of full=3000
times both sides by 12/5
full=7200

the capacity is 7200 cubic inches

Figure it out your self