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If a box contains 10 bulbs,of which just three are defective. If a random sample of five bulbs is drawn, find the probability that the sample contains no defective bulbs.

If a box contains 10 bulbs,of which just three are defective. If a random sample of five bulbs is drawn, find the probability that the sample contains no defective bulbs. Correct Answer 1\/12

Total number of elementary events = 10C5

 

Number of ways of selecting no defective bulbs i.e., 5 non-defective bulbs out of 7 is 7C5.

 

So,required probability =7C5/ 10C5 = 1/12.

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