There is a bag filled with 4 blue, 3 red and 5 green marbles. A marble is taken at random from the

Discussion in 'Calculator Requests' started by math_celebrity, Oct 28, 2018.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    There is a bag filled with 4 blue, 3 red and 5 green marbles. A marble is taken at random from the bag, the colour is noted and then it is replaced. Another marble is taken at random. What is the probability of getting 2 blues?

    We have (4 blue + 3 red + 5 green) = 12 total marbles

    With replacement, the probability of getting one blue is 4/12 = 1/3

    Since each draw is independent of the last, the probability of Blue, Blue = 1/3 * 1/3 = 1/9
     

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