SOLUTION: A bag contains 12 marbles, one marble is drawn. The probability of drawing a blue is 1/3 and the probability of drawing a red or a blue is 1/2. How many of the marbles are red

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Question 326136: A bag contains 12 marbles, one marble is drawn. The probability of drawing a blue is 1/3 and the probability of drawing a red or a blue is 1/2. How many of the marbles are red
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
+P%28B%29=1%2F3=B%2F12+
+B=4
4 blue marbles
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.
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+P%28B+or+R%29=P%28B%29%2BP%28R%29=1%2F2
1%2F3%2BP%28R%29=1%2F2
2%2F6%2BP%28R%29=3%2F6
P%28R%29=1%2F6
R%2F12=1%2F6
R=2
2 red marbles