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Given 24 pens, either red or blue. If 4 are blue, what is the probability of you select 2 pens AT LEAST 1 will be blue. (without replacement, that is, you are taking 2 separate pens)

  • Probability -

    Add the probabilities of:
    blue-red, red-blue and blue-blue.
    (4/24)*(19/23) + (20/24)*(4/23) + (4/24)(3/23) = [76 + 76 + 12)/552 = 164/552
    = 41/138

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