The correct option is : [tex]60 ft^3[/tex]
Explanation
Suppose, the volume of the fish tank is [tex]V[/tex] ft³
The density of the fish tank is 0.5 fish/ft³. It means, the number of fish in 1 ft³ volume is 0.5
So, the number of fish in [tex]V[/tex] ft³ volume will be: [tex]0.5V[/tex]
Given that, there are 30 fish in the tank. So, the equation will be......
[tex]0.5V=30\\ \\ V=\frac{30}{0.5}=60[/tex]
Thus, the volume of the tank is 60 ft³
