A box contains ten bulbs out of which 5 are defective. If four bulbs are chosen at random, find the probability that exactly two bulbs are good?
Choose the most appropriate option
A) 7/21 B) 10/21 C) 9/21 D) 8/21 E) 5/21
Required probability = (5C2 . 5C2)/10C4 = (10 * 10)/210   = 10/21   Answer:10/21
<result>B</result>
A box contains ten bulbs out of which 5 are defective. If four bulbs are chosen at random, find the probability that exactly two bulbs are good?