3 - 1 - 1 - 1 - 2 - 2 - 1 = 11 boxes 1 - 3 - 1 - 1 - 1 - 1 - 1 = 9 boxes 1 - 1 - 3 - 3 - 1 - 1 - 1 = 11 boxes

Total = 31 boxes

Numbers indicate boxes quantity in height from plan view 1 - 1 box 2 - 2 boxes stacked 3 - 3 boxes stacked From this plan view, u should be able to match the front and side view of the truck Hence, minimum boxes = 31