ANSWER :
2040 in^3
EXPLANATION :
From the problem, we have an aquarium.
If we divide the solid into two parts, we will have two rectangular prisms :
The big prism is 10 in by 12 in by 14 in.
The small prism is 5 in by 12 in by (20 - 14 = 6) 6 in
The volume formula of a prism is :
The volume of the solid is the sum of the volumes of two prisms.
That will be :