Question 254695: A bag contains 7 red balls numbered 1,2,4,5,6,7 and 3 white balls numbered 3,8,9. If a ball is drawn at random, what is the probability the ball is:
A. red or odd numbered?
B. white or even numbered>
Answer by drk(1908)   (Show Source):
You can put this solution on YOUR website! If we look at the given information, there are 6 red and 3 white, not 7 and 3. I will use the 6 and 3 numbering:
(i) P(red or odd) means
(ii) P(red) + p(odd)
P(red) = 6/9
P(odd) = 5/9
however, some red are also odd and need to be subtracted, so we adjust (ii) to get
(iii) P(red) + p(odd) - p(red and odd).
So, we get
P(red) + p(odd) - p(red AND odd) = 6/9 + 5/9 - 3/9 = 8/9
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(B) P(white or even) = P(white) + p(even) - P(white AND even)
P(white or even) = 3/9 + 4/9 - 1/9 = 6/9 = 2/3
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