The volume of an open-top box is $30\text{ in}^3$. The length of the base is twice the width.  

1. Sketch a labeled diagram.

   Hint (a):

   Sketch a box. Label the height $h$ and the sides of the base $x$ and $2x$.

2. Express the total outside surface area, $S$, in terms of the width, $x$. Simplify.

   Step (b):

   $S=x·2x+x·h+2x·h+x·h+2x·h$

3. What width will minimize the surface area?

   Hint (c):

   Graph your function from part (b) and locate the minimum point.