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Analysis: blue 3 3+2+4 = 9 total marbles
red 2
green 4
Probability of two blue = 3/9 x 2/8 = 1/12 = 3/36
Probability of two red = 2/9 x 1/8 = 1/36
Probability of two green = 4/9 x 3/8 = 1/6 = 6/36
Probability pf two the same = 3/36 + 1/36 + 6/36 = 5/18
The probability of getting two of the same colour is 5/18. In order to determine the percentage you must divide 5 by 18 and mulitply x 100 and round it. (5/18 = 0.2777777777777778 x 100 = 27.77777777777778 about 27%)