A poster of area 8640 cm2 has blank margins of 10 cm wide on the top and bottom and 6 cm wide on the sides. Find the dimensions that maximize the printed area

Answer 1

Draw and label a diagram

W represents the width of the poster

L represenbts the length (height) of the poster

W = 8540 / L

Dimensiob of printed area

width is (8640 / L) - 12

height is L - 20

area is [(8640 / L) - 12](L - 20)

set first derivative to zero and solve for L