Rectangular Box 

In his arts and crafts class, Tony is given
a piece of paper and asked to make a rectangular box. The length
of the box he created is 3 times of its width. His friends made boxes
with various lengths, widths and heights. He wonders how the height
changes affects the width.
What is known:
 The surface area of the box is constant at 100 in^{2}.
 The length is 3 times of its width.
