A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that exactly three bulbs are good
Select
A) 20/63	B) 4/56	C) 8/7	D) 6/9	E) 4/9
Explanation:   Required probability = (âµCâ‚ƒ . â´Câ‚)/â¹Câ‚„ = (10 * 4)/126 = 20/63   20/63nswer: 20/63
<result>A</result>
A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that exactly three bulbs are good