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    i have two questions that i have answered, but unsure about my working and so unsure about my answers. Can someone please tell me whether my answers are correct.

    1. Two events A and B are such that P(A) = 1/2, P(A|B') = 2/3 and P(A|B) 3/7. Find:
    a) P(A intersect B)
    b) P(A union B)
    c) P(B)
    d) P(B|A)
    State with reasons whether A and B are i) independent, ii) mutually exclusive.

    2. The probability that a door to door slaesman convinces a customer to buy his products is 0.7. Assuming that sales are independent, find the probability that the salesman makes a sale before reaching the fourth house.


    1. a) 1/6
    b) 13/18
    c) 7/18
    d) 1/3

    i) I got A and B are not independent because P(A) * P(B) is not equal to P(A intersect B)
    ii) I got A and B are not mutually exclusive as P(A intersect B) is not equal to 0.

    2. i got: 0.9919

    Can someone please tell me whether these answers are correct, and if not, can you tell me how to go about it.

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Updated: November 15, 2008


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