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. Select:
A) 1/166
B) 1/129
C) 1/526
D) 1/121
E) 1/126
Out of nine, five are good and four are defective. Required probability = 4C4/9C4 = 1/126.Answer: 1/126
<result>E</result>
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.