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    Howdy . I have attached the question and answers I am working on.

    I don't understand part b(ii). I get that P(B U T) is 10 + 8 + 4 + 6 + 11 + 3 = 42 which is the bottom part of the fraction as of the 'given by |' part.

    I just don't get why we only use 15 for P(Z)

    Wouldn't we take all the Z values for P(Z). 15 + 3 + 4 + 8.

    I just don't get how we take 15 for the numerator. Could some please explain?

    Thanks
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    (Original post by jojo55)
    Name:  Venns.jpg
Views: 17
Size:  54.8 KB

    Howdy . I have attached the question and answers I am working on.

    I don't understand part b(ii). I get that P(B U T) is 10 + 8 + 4 + 6 + 11 + 3 = 42 which is the bottom part of the fraction as of the 'given by |' part.

    I just don't get why we only use 15 for P(Z)

    Wouldn't we take all the Z values for P(Z). 15 + 3 + 4 + 8.

    I just don't get how we take 15 for the numerator. Could some please explain?

    Thanks
    You need to use the rule P(A|B) = P(A n B)/P(B)

    Identify which bit of the Venn Diagram gives you P(Z n (B u T)), and which bit gives you P(B u T), then divide

    Both probabilities will be out of 70, so you can do some cancelling.
 
 
 
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