



 
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 crnl  


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