300
Barbara filled a box with layers of unit cubes. The box had a volume of 125 cubic units. Which sentence about the box must be true?
a. There were 125 unit cubes in the bottom layer.
b. The box was filled with exactly 125 unit cubes.
c. There were 125 unit cubes in each layer.
d. The box was filled with less that 125 unit cubes.
What is b. The box was filled with exactly 125 unit cubes.