Answer:
72 defective light bulbs
Explanation:
Out of 500 total light bulbs only 3 were defective.
If we created 12 000 total light bulbs, that's 24 times the amount. So that means we expect 24 times the amount of defective light bulbs to also be produced:
3 x 24 = 72
3 : 500
x 24
72 : 12 000