A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that atleast one bulb is good.
Options:
(A) 6/63
(B) 2/63
(C) 125/126
(D) 1/126
(E) 1/63 Hmmm, my stream of consciousness:
Required probability = 1 - 1/126 = 125/126 So, the answer is (C).