A carton of 24 bulbs contain 6 defective bulbs. One bulb is drawn at random. What is the probability that the bulb is not defective? If the bulb selected is defective and it is not replaced and a second bulb is selected at random from the rest, what is the probability that the second bulb is defective?

Total number of bulbs, n(s) = 24


Let E1 = Event of selecting not defective bulb = Event of selecting good bulbs


n(E1) = 18



Suppose, the selected bulb is defective and not replaced, then total number of bulbs remains in a carton, n(S) = 23


In them, 18 are good bulbs and 5 are defective bulbs.


∴ P(selecting second defective bulb) = 5/23


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