Answer:
The correct answer is 75 cubic feet.
Explanation:
Volume of each block of cube is 1 cubic foot. Since the block is of the shape of a cube, the side length is 1 foot.
Number of blocks needed to fill the bottom of the the chest is 25.
Height of the chest is 3 feet.
Therefore there are three layers to be filled by blocks. Each layer needs 25 blocks each. Thus number of blocks needed to fill the whole chest is 25 × 3 = 75.
Volume of 75 blocks = Volume of the chest = 75 × 1 = 75 cubic feet.
Therefor the volume of the chest is given by 75 cubic feet.