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Hi guys

This one is kind of embarrassing, but its driving me crazy! I am working through some examples in a prob. book, to try and refresh my rusty stats and prob knowledge. There is a question that goes: "There are 8 olive, 4 black, and six brown socks in a drawer. Two are selected at random. What is (a) the probability that the two socks are the same color? (b) If they are the same color, what is the prob. that they are both olive?"

I can figure out part (a), which is:

[itex]

\frac{\dbinom{4}{2}+\dbinom{8}{2}+\dbinom{6}{2}}{\dbinom{18}{2}}

[/itex]

But I cant figure out P(olive|same color). Can anyone help?

Thanks

Rory

Oh BTW, this isnt a homework question - I can see the answer from the back of the book is 4/7 - Im just curious to see how the author got it! Thanks.

This one is kind of embarrassing, but its driving me crazy! I am working through some examples in a prob. book, to try and refresh my rusty stats and prob knowledge. There is a question that goes: "There are 8 olive, 4 black, and six brown socks in a drawer. Two are selected at random. What is (a) the probability that the two socks are the same color? (b) If they are the same color, what is the prob. that they are both olive?"

I can figure out part (a), which is:

[itex]

\frac{\dbinom{4}{2}+\dbinom{8}{2}+\dbinom{6}{2}}{\dbinom{18}{2}}

[/itex]

But I cant figure out P(olive|same color). Can anyone help?

Thanks

Rory

Oh BTW, this isnt a homework question - I can see the answer from the back of the book is 4/7 - Im just curious to see how the author got it! Thanks.

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