A box contains seven bulbs out of which 3 are defective. If three bulbs are chosen at random, find the probability that all the four bulbs are defective?  Select: A) 1/35 B) 1/12 C) 1/18 D) 1/198 E) 1/126
Out of seven, four are good and three are defective. Required probability   = 3C3/7C3   = 1/35   1/35nswer: 1/35
<result>A</result>
A box contains seven bulbs out of which 3 are defective. If three bulbs are chosen at random, find the probability that all the four bulbs are defective?