check the picture below.
now, we know the conveyor does 75 feet in 1 minute, how many minutes will it take for 30 feet?
[tex]\bf \begin{array}{ccll}
feet&minutes\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
75&1\\
30&m
\end{array}\implies \cfrac{75}{30}=\cfrac{1}{m}\implies m=\cfrac{35\cdot 1}{75}\implies m=\cfrac{7}{15}[/tex]
so, it takes 7/15 of a minute, which is 28 seconds, or 0.47 minutes.