SOLUTION: Single cards chosen at random are given away with boxes of Weetbix. Each card shows a picture of one of 25 All Blacks. Diane needs just one picture to complete her collection. She
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Question 611529: Single cards chosen at random are given away with boxes of Weetbix. Each card shows a picture of one of 25 All Blacks. Diane needs just one picture to complete her collection. She buys 3 boxes of Weetbix and looks at all the pictures. Find the probability that
a) Diane does not complete her collection.
b) She has the required picture exactly twice
c) She completes her collection with the second picture she looks at Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Single cards chosen at random are given away with boxes of Weetbix. Each card shows a picture of one of 25 All Blacks. Diane needs just one picture to complete her collection. She buys 3 boxes of Weetbix and looks at all the pictures.
Binomial Problem with n = 3 and p(needed pic) = 1/25 ; P(other pic) = 24/25
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Find the probability that:
a) Diane does not complete her collection.
Ans : (24/25)^3 = 0.885
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b) She has the required picture exactly twice
Ans: 3C2*(1/25)^2(24/25) = binompdf(3,1/25,2) = 0.0046
c) She completes her collection with the second picture she looks at
Ans: (24/25)(1/25) = 24/625
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Cheers,
Stan H.
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