Question 466673

Use Bye's theorem of probability.

Superior : 15 are good, 10 are fair, and 5  are poor 

other :  5 are good, 10  are fair, and 15 are poor.



Probability that fair from superior and poor from other = 10/30 * 15/30 = 1/6 


probability that fair from other and poor from superior :  10/30 * 5/30 = 1/18 



required probability =  (1/6) / [ 1/6 + 1/18]

= (1/6) / [4/18]

= 3/4


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