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    Hi,
    I've been practicing s1 edexcel past papers to prepare for my exam but i find Venn diagrams really confusing. On one of the papers, i'm stuck on one of the questions and still don't understand it after looking at the mark scheme :confused:

    Here's a link to the question paper,

    S1 Jan 2006

    it's question 6c

    Here's a link to the mark scheme if you want to look at that,

    Mark scheme

    Can someone explain it to me please?

    Thank You (^_^)
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    Formula for conditional probability is: P(A|B) = P(AnB)/P(B)
    So here: P(A|B') = P(AnB')/P(B')

    Now P(B') = 0.32+0.35=0.67, the parts outside the circle B since B' means the event "not B".
    AnB' is the event "A occurs but B does not", so it's just the left hand side of the venn diagram, 0.32.

    So answer is 0.32/0.67 = 0.478
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    (Original post by vc94)
    Formula for conditional probability is: P(A|B) = P(AnB)/P(B)
    So here: P(A|B') = P(AnB')/P(B')

    Now P(B') = 0.32+0.35=0.67, the parts outside the circle B since B' means the event "not B".
    AnB' is the event "A occurs but B does not", so it's just the left hand side of the venn diagram, 0.32.

    So answer is 0.32/0.67 = 0.478
    Ah I understand it now. I think I just need to practice a lot more lol, thank you!!
 
 
 
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