I got a/b and computed a times b. But 2a/2b is a perfectly acceptable answer; that would then give the integer 4ab rather than ab. Why does the submitted answer have to be an integer anyway. What's wrong with submitting the decimal value answer, say, in the form 0.something ? Furthermore, it is possible to get the wrong answer and still be marked right eg. if a = 5 and b = 2/5

Bob

ps. I didn't use the Bayes formula. This is because I cannot be bothered to learn formulas ever. I have found that a tree diagram works fine and is easier to explain to others.

]]>I am a moderator there and I reported the problem for being Kaboobly Doo. So, the problem poser changed the problem now.

Can you solve the new version?

]]>What site is that ? I'd like to view from the beginning.

Bob

]]>This solution assumes that P(A) = P(B) = P(C) = P(D) = 1/4.

There's nothing in the wording of the problem that allows these assumptions. For all we know, there might only be 2 whites, in which case P(D) = 1 and the rest are zero.

Bob

]]>]]>PIf P(A)=probability of getting the bag chosen for drawing balls when all the 5 balls in the bag are white.

P(B)=probability of getting the bag chosen for drawing balls when only 4 balls in the bag are white

P(C)=probability of getting the bag chosen for drawing balls when only 3 balls in the bag are white

P(D)=probability of getting the bag chosen for drawing balls when only 2 balls in the bag are white

P(E)=probability of getting two white balls drawn from the bag

P(E/A)=probability of two white balls drawn when the bag is chosen which has all white balls in it

P(E/B)=probability of two white balls drawn when the bag is chosen which has only 4 white balls in it

P(E/C)=probability of two white balls drawn when the bag is chosen which has only 3 white balls in it

P(E/D)=probability of two white balls drawn when the bag is chosen which has only 2 white balls in it.

So using baye's theorem

required probability

Let me show you the solution and please tell me if you can digest it.

]]>It isn't a Bayes problem, as there are not two events.

Bob

]]>What is the probability that all the balls are white?

]]>