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# S1 Help watch

1. Quick question, with the equation P(AnB)/P(B), how do you calculate P(AnB)?

http://www.mei.org.uk/files/papers/s108ju_rfs6.pdf question 6ii, the mark scheme says it's just 0.04/0.9801, which is just P(A)/P(B). I'm very confused, please help.
2. (Original post by Guills on wheels)
Quick question, with the equation P(AnB)/P(B), how do you calculate P(AnB)?

http://www.mei.org.uk/files/papers/s108ju_rfs6.pdf question 6ii, the mark scheme says it's just 0.04/0.9801, which is just P(A)/P(B). I'm very confused, please help.
You mean P(A) / P(C) don't you?

If you use the formula for P(A|C) in terms of P(A n C) and P(C) and think about what the event A n C actually means (read it to yourself in words) you should be able to see where they've got the numbers from
3. (Original post by davros)
You mean P(A) / P(C) don't you?

If you use the formula for P(A|C) in terms of P(A n C) and P(C) and think about what the event A n C actually means (read it to yourself in words) you should be able to see where they've got the numbers from
well yeah for the question. A and B were just arbitrary, they didn't relate to the question

I eventually managed to figure that one was a subset of the other, but thank you anyway
4. aw man I was stalking you and I saw this thread and thought 'ah yes my time has come'

I did S1 last year c;

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