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 $\displaystyle xy=30$

Since there is a margin on top and on bottom of 2 inches each, the height of the paper will be $\displaystyle y+4$

And since there are two lateral margins of 1 inch each, the length of the paper will be $\displaystyle x+2$

Hence the area of the paper will be $\displaystyle A=(x+2)(y+4)$

So find x and y such as A is minimized, and remember that $\displaystyle xy=30$

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