Question

An 80-pound bag of concrete mix will yield 0.6 cubic feet of concrete. Each bag costs $4.98. An artist wants to make a concrete sculpture consisting of three cubes, one on top of the other. The cube at the base will be 3 ft x 3 ft x 3 ft. The next cube will be 2 ft x 2 ft x 2 ft. The third cube will be 1 ft x 1 ft x 1 ft.

How much will the materials cost for the sculpture cost?

Answer 1

It will cost $298.80.

We first find the volume of each cube in the sculpture. The volume of a cube is given by the formula:

V = s³

For the largest cube, we have

V = 3³ = 27 ft³

For the middle cube, we have

V = 2³ = 8 ft³

For the smallest cube, we have

V = 1³ = 1 ft³

The sum of these would be 27 + 8 + 1 = 36 ft³

Each bag holds 0.6 ft³ of concrete; we divide our total volume by this:

36/0.6 = 60

It will take 60 bags. At 4.98 per bag, the cost would be
60(4.98) = 298.80.