Hello,

Suppose that the printed part is a rectangle of sides x and y (x will be the length, y the height). And assuming that the paper is rectangular..

The area of the printed part is

Since there is a margin on top and on bottom of 2 inches each, the height of the paper will be

And since there are two lateral margins of 1 inch each, the length of the paper will be

Hence the area of the paper will be

So find x and y such as A is minimized, and remember that

Hence I'd advise you to develop the expression for A