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Bag of 4 color balls

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by harsh.champ » Wed Feb 17, 2010 5:55 am
A bag contains 7 red, 5 blue, 4 white and 4 black balls. Find the probability that a ball drawn at random is red or white.


A.11/20
B.19/20
C.1/17
D.12/20
E.18/20
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by ajith » Wed Feb 17, 2010 6:04 am
harsh.champ wrote:A bag contains 7 red, 5 blue, 4 white and 4 black balls. Find the probability that a ball drawn at random is red or white.


A.11/20
B.19/20
C.1/17
D.12/20
E.18/20
Probability that one will draw a white ball = 4/20
Probability that one will draw a red ball = 7/20

Since these events are mutually exclusive total probability is = 4/20+7/20 = 11/20
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