SOLUTION: A box contains 3 blue and 4 red marbles while another box contains 2 blue and 5 red marbles. A marble drawn at random from one of the boxes turns out to be blue. What is the probab

Question 1178073: A box contains 3 blue and 4 red marbles while another box contains 2 blue and 5 red marbles. A marble drawn at random from one of the boxes turns out to be blue. What is the probability that it came from the first box?
Answer by ikleyn(53765) (Show Source): You can put this solution on YOUR website!
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A box contains 3 blue and 4 red marbles while another box contains 2 blue and 5 red marbles. A marble drawn at random
from one of the boxes turns out to be blue. What is the probability that it came from the first box?
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You can compute this probability in two different ways.


One way is  P =  =  =  =  =  = 0.6 = 60%.


This formula is the version of the conditional probability in the full space of events.



The other way is P =  =  =  = 0.6 = 60%.


This formula is the version of the conditional probability in the reduced space of events.



    Both formulas are SELF-EXPLANATORY,

    and both formulas give THE SAME answer.

Solved.

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