To find out how much area he will paint, you will find the area of all 6 faces.
Each face is in the shape of a rectangle, so use A = lw as your formula.
Front/Back: 80 x 36 = 2880 square inches
2880 square inches x 2 = 5760 square inches
Right/Left Sides: 80 x 2 = 160 square inches
160 square inches x 2 = 320 square inches
Top/Bottom: 36 x 2 = 72 square inches
72 square inches x 2 = 144 square inches
5760 + 320 + 144 = 6224 square inches.
Cody will paint 6224 square inches.