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. Choose the correct option.
A) 1/127 B) 1/191 C) 1/138 D) 1/132 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.