Bag A contains 3 red and 4 black balls and bag B contains 4 red and 5 black balls. One ball is transferred from bag A to bag B and then a ball is drawn from bag B. The ball so drawn is found to be red in colour. Find the probability that the transferred ball is black.

Question

anonymous · Answer

well, there are only 7 in bag a, and youre only transferring 1. so what probability is that?

anonymous · Answer

A 3/7 chance of transferring a red ball or 4/7 chance of transferring a black ball.

Gotta use baye's theorem but I'm a bit confused of what

Event A will be
P(E1|A) is
P(E2|A) is

Is E1|A the probability of red ball being transferred?

Will that be.. P(A|E1) x P(E1)/P(E1) x P(A|E1) + P(E2) x P(A|E2)?

anonymous · Answer

3/7 x 1/2/1/2 x 3/7 + 1/2 x 4/7

= 3/7

P.S sorry for the late reply! I'm making notes to identify probability questions, kinda hard to know what formula to use for each question[conditional/independent/baye's/binomial distribution]

anonymous · Answer

is 3/7 the right answer? even if it is, I'll probably lose 50% because no steps -.-

rational · Answer

wait

rational · Answer

im getting 16/31

anonymous · Answer

how?

rational · Answer

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