[tex]30\:sec[/tex]
1) Since a carton resembles a rectangular prism, we can solve it for the volume once we have 3 measurements and the volume of a rectangular prism is found by the product of those three dimensions (width, height, and length).
2) So, we can write out the following (setting a proportion):
[tex]\begin{gathered} V=3\times2\times2=12\:ft^3 \\ V=4\times5\times6=120\:ft^3 \\ 12----3\:seconds \\ 120----x \\ \\ \frac{12}{120}=\frac{3}{x} \\ \frac{1}{10}=\frac{3}{x} \\ x=3\cdot10 \\ x=30\:sec \\ \end{gathered}[/tex]
