Answer:
C. 6 kg
Step-by-step explanation:
Let m represent the mass of plates on one side of the barbell. Then the total weight of the barbell is ...
2m +24 = 60 . . . . . kilograms
m +12 = 30 . . . . . . . divide by 2
m = 18 . . . . . . . . . . . subtract 12
The mass of plates on one side of the barbell must total 18 kg. If they all have the same mass, then that must be a divisor of 18. In whole numbers, that would include plates of mass 1, 2, 3, 6, 9, 18 kg.
The only one of these on your list of answer choices is ...
6 kg
