If the cube is melted down and the metal used to make 32,000 identical ball bearins, what is the weight, in pounds, of one of these ball bearings?

Question

The full question:

 

A metal cube with sides of length 2 feet has a uniform density of 100 pounds per cubic foot. If the cube is melted down and the metal used to make 32,000 identical ball bearins, what is the weight, in pounds, of one of these ball bearings?

 

Please help. The way I did it was wrong. I need help. Thank you!

Answer 1

First find the volume of the cube.  That's equal to the third power (cube) of the length of one side.  So the volume is 8 cubic feet.

 

Since the density is 100 pounds per cubic foot, the overall weight is 800 pounds.

 

To find the weight of one of the ball bearings, divide 800 by 32000 = 1/40 = 0.025 pounds.  Since there are 16 ounces in a pound, you can also say that the weight of one bearing is 0.4 ounces.