no27fiorano Posted July 20, 2005 Share Posted July 20, 2005 A bag contains 3 red, 4 black and 2 white balls. what is the probability of drawing a red and a white ball in each successive draws, each ball being put back after it is drawn? a) 2/27 b) 1/9 c) 1/3 d) 4/27 e) 2/9 Quote Link to comment Share on other sites More sharing options...
ajaykn Posted July 20, 2005 Share Posted July 20, 2005 I would think 4/27. P(red) 3/9 = 1/3 P(white) 2/9 - since the first ball was replaced. P(red, white) 1/3 * 2/9 = 2/27 Since it is also possible to get white ball first and then red, there are 2 ways of getting red and white in successive draws. 2/27 * 2 = 4/27 Does the logic make sense? Quote Link to comment Share on other sites More sharing options...
no27fiorano Posted July 21, 2005 Author Share Posted July 21, 2005 I got 2/27 as my ans. but it makes sense what you have done. Thnaks Quote Link to comment Share on other sites More sharing options...
manisha patil Posted August 1, 2005 Share Posted August 1, 2005 ans =2/27 ans =3/9*2/9 if they asked abt Red & black ball then ans would be 4/27 Quote Link to comment Share on other sites More sharing options...
manasi4gre Posted August 1, 2005 Share Posted August 1, 2005 I would go for 4/7. Probability(R,W) in each successive draw = 2(2/7) =4/7. Quote Link to comment Share on other sites More sharing options...
kittie Posted August 7, 2005 Share Posted August 7, 2005 i would go by 4/27. What is the OA? Quote Link to comment Share on other sites More sharing options...
coolprasant Posted August 8, 2005 Share Posted August 8, 2005 The question refers to "drawing a red and a white ball in each successive draws". That means a RED first and then WHITE and not the other way round so the answer will be 1/3*2/9=2/27 and not 4/27. Whats the OA?? Quote Link to comment Share on other sites More sharing options...
pranay Posted August 8, 2005 Share Posted August 8, 2005 4/27 should be the answer. what is OA Quote Link to comment Share on other sites More sharing options...
jsr_idhar Posted August 11, 2005 Share Posted August 11, 2005 I got 2/27 too The question refers to "drawing a red and a white ball in each successive draws". That means a RED first and then WHITE and not the other way round so the answer will be 1/3*2/9=2/27 and not 4/27. Whats the OA?? Quote Link to comment Share on other sites More sharing options...
RamN Posted July 8, 2008 Share Posted July 8, 2008 Shud be 4/27 = 2/27* 2... Coz possibility of drawing red and white and the other case of white and red has to be considered Quote Link to comment Share on other sites More sharing options...
ssky Posted July 10, 2008 Share Posted July 10, 2008 The question is specific about the order..first red and then white in successive draws so 2/27 should be the answer. Quote Link to comment Share on other sites More sharing options...
yuvrajl Posted July 29, 2008 Share Posted July 29, 2008 4/27 would be the ans... Quote Link to comment Share on other sites More sharing options...
gmatbuster Posted July 29, 2008 Share Posted July 29, 2008 Probability for Red ball = 3C1/9C1= 1/3 Probability for White ball = 2C1/9C1= 2/9 for Red followed by white = 2/27 ...i for White followed by red = 2/27 ....ii Total = i +ii = 4/24 Quote Link to comment Share on other sites More sharing options...
ramiy Posted July 31, 2008 Share Posted July 31, 2008 Whats the OA No27 ? Quote Link to comment Share on other sites More sharing options...
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