SOLUTION: A box contains 4 blue balls, 7 red balls, and 5 white balls. If one ball is selected at random, find P(blue/not white).

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Question 1174142: A box contains 4 blue balls, 7 red balls, and 5 white balls. If one ball is selected at random, find P(blue/not white).
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!



P(blue|not white) = 4/(4+7) = +highlight%28+4%2F11+%29+



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You can also apply Bayes' Theorem for conditional probabilities:



P(A|B) = P(B|A)*P(A) / P(B)



We assign events

A = ball selected is blue

B = ball selected is not white



P(A) = 4/(4+7+5) = 4/16

P(B) = (4+7)/16 = 11/16

P(B|A) = 1  (if it is blue it is certainly not white)



P(A|B) = 1*(4/16)/ (11/16) = 4/11,  just as before.