- A21/55
- B1/4
- C34/55
- D27/55
Step-by-Step Solution
Total selections = C(12,3) = 220. Selections with no defective bulb = C(9,3) = 84, a probability of 84/220 = 21/55. By the complement rule P(at least one defective) = 1 − 21/55 = 34/55.
Answer: C) 34/55