Answer:
Supposing the three boxes are in the shape of cuboid.
Area of base of each box = 16 square feet
Height of two boxes which are identical = 3 feet
Height of third box= 5 feet
Volume of Box = Area of Base × Height
Total Volume of three boxes = 16 × 3+16 ×3 +16 × 5
= 48 +48 +80
=96 +80
= 176 cubic feet