Final answer:
The minimum number of compartments in the utility box is 0.
Step-by-step explanation:
The minimum number of compartments in the utility boxes can be calculated by subtracting 175 from 21.
Minimum number of compartments = 21 - 175
Since the result of this subtraction is a negative number, it is not possible to have a negative number of compartments in a utility box. In this case, the answer would be 0 compartments.