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# What is the probability that the marble is red, given it came from bag A?

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• Probability of chosing bag A: 1/3
• Probability of chosing bag B: 2/3
• Bag A has 35 red marbles with 65 blue marbles.
• Bag B has 55 red marbles with 45 blue marbles

If I get a red marble, what is the probability it came from bag A?

Nov 19, 2017

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The probability of choosing a red marble from bag A:  (1/3) x (35/100)  =  7/60

The probability of choosing a red marble from bag B:  (2/3) x (55/100)  =  22/60

The probability of getting a red marble is 29/60.

Getting that red marble from bag A is  7/60 / 29/60  =  7/29.

Getting that red marble from bag B is  22/60 / 29/60  =  22/29.

Nov 19, 2017

#1
+17747
+1

The probability of choosing a red marble from bag A:  (1/3) x (35/100)  =  7/60

The probability of choosing a red marble from bag B:  (2/3) x (55/100)  =  22/60

The probability of getting a red marble is 29/60.

Getting that red marble from bag A is  7/60 / 29/60  =  7/29.

Getting that red marble from bag B is  22/60 / 29/60  =  22/29.

geno3141 Nov 19, 2017