If h varies inversely to s, then we can use the next equation:
[tex]h=\frac{k}{s}[/tex]Then, when s= 60 and h=5.
Replacing:
[tex]5=\frac{k}{60}[/tex]Solve for k:
[tex]\begin{gathered} k=5\ast60 \\ k=300 \end{gathered}[/tex]Now, if s=75 and k=300:
[tex]\begin{gathered} h=\frac{300}{75} \\ h=4 \end{gathered}[/tex]Hence, it will take 4 hours.