Math CentralQuandaries & Queries


Question from jan, a student:

9 marbles are placed in a bag. 4 are blue, 3 are green, 2 are red. what is the probability of the following: a)p(g) (b) p(b) (c) p(r or g)

Hi Jan,

For probability we need to place the number of the particular colour desired over the total number of marbles. For example say there are 5 blue, 6 red and 7 green. p(g) = # of green/total number... or 7/(5+6+7) = 7/18 or approx. 0.3888888888888
In the case of the "or" then p(b or g) = (5 + 7)/18 = 12/18 = 2/3 or approx. 0.6666666666666666

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