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# Probability (S1) watch

1. Hi,

I'm stuck on this question and would really appreciate any help:

Two events R and S are independent. P(R|S) = 3/4 and P(S) = P(S' and R'). By letting x equal P(S) and forming an equation for x, or otherwise, find:

a) P(S)
b) P(S' and R)
c) Write down P(S|R)

Thanks.
2. Can you post your working so far?
3. P(R|S) = P(R and S)/P(S)

0.75 = P(R and S)/P(S' and R')

I'm not sure this is right because the question says that P(S) = P(S' and R') but then says by letting x equal P(S)?
4. Well, if P(S) = x
Then P(S') = 1-x

Try solving it algebraically, starting like that.

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Updated: July 14, 2008
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