Question

The outside of an aquarium tank is 50 cm long, 40 cm wide, and 20 cm high. It is open at the top. The glass used to make the tank is 1 cm thick. What is the inside volume of the tank?

Answer 1

we know that

[inside volume of the tank]=[40-2]*[50-2]*[20-1]------> (the top is open)
[inside volume of the tank]=[38]*[48]*[19]----> 34656 cm³

the answer is
the inside volume of the tank is 34656 cm³