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A bag contains 4 blue marbles, 5 red marbles, and 7 green marbles. If two marbles are...

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utilityfan | Student, College Freshman | Valedictorian

Posted May 23, 2012 at 1:53 PM via web

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A bag contains 4 blue marbles, 5 red marbles, and 7 green marbles. If two marbles are drawn without any replacement, what is the probability that:

a) Both marbles are blue.

b) At least one marble is red.

c) The marbles are not of the same color.

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted May 23, 2012 at 2:01 PM (Answer #1)

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The bag contains 4 blue marbles, 5 red marbles, and 7 green marbles. Two marbles are drawn without replacement.

The probability that both the marbles are blue is `(4/16)(3/15) = 0.05`

The probability that at least one marble is red is `2*(5/16)*(11/15) + (5/16)*(4/15) = 0.54`

The probability that the marbles are not of the same color is `(4/16)*(12/15) + (5/16)*(11/15) + (7/16)*(9/15) ~~ 0.691`

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cornert07 | College Teacher | (Level 2) Adjunct Educator

Posted May 23, 2012 at 2:32 PM (Answer #2)

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A= 0.05 (0.25x0.2)

B = 0.54 (2x0.3125x0.7333)+(0.3125x0.2666)

C= 0.69 (0.25x0.8)+(0.3125x0.7333)+(0.4375x0.6)

Hope that helps!!!

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