A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that all the four bulbs are defective.
62/63
125/126
1/63
1/126
Explanation:
Out of nine, five are good and four are defective. Required probability = ⁴C₄/⁹C₄ = 1/126
Out of nine, five are good and four are defective. Required probability = ⁴C₄/⁹C₄ = 1/126