Given data:
The length of the tank is l=5 feet.
The width of the tank is b=4 feet.
The half volume of the tank is V=75 cubic-feet.
The expression for the half volume is,
[tex]V=\frac{1}{2}(l\times b\times h)[/tex]Substitute the given values in the above expression.
[tex]\begin{gathered} (75\text{ cubic-ft)=}\frac{1}{2}(5\text{ ft)(4 ft)(h)} \\ h=7.5\text{ ft} \end{gathered}[/tex]Thus, the height of the tank is 7.5 feet.
