first you need to find the area of the floor to know how much wood you need
Area=lengthxwidth, so A=40x14.5 which equals 580 square ft
With a floor that's 580 square ft and the boxes cover 18 Sq ft each then all you have to do is 580/18= 32.222 and because you can't buy .222 of a box you need to round up to 33 boxes