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**scorpion007** Suppose there are two bags A and B and a set of colored balls (red and green).

Partially color-blind people are told to place all the red balls in A and the green balls in B.

Their ability to distinguish the balls is 80% reliable.

15% of the balls are red, the rest green. (85%)

If we randomly choose a ball from bag A, what is the probability of it being red? (or green)?

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My work:

We know that P(R) = .15, P(G) = .85.

I think we need something like P(R|A) = ?

Not sure how to proceed

EDIT: Ah! I think I see. I think that P(A | R) = .8 and P(B|R)=.2, etc... is that right?

EDIT 2: Hmm.. no, still not sure what P(A) should be though...