A rectangular page is designed to contain 64 inches of print. The margins at the top and bottom of the page are each 1 inch deep. The margins on each side are 1.5 inches wide. What should the dimensions of the page be so that the least amount of paper is used?

Answer 1

if the print area is x by y inches, then the paper size is
p = (x+3)(y+2) = (x+3)(64/x + 2) = 2x+70 + 192/x
This has a minimum at x = 4√6
so now calculate y.