There are 3 urns A,B and C,A contains 4 red balls and 3 black balls.Urn B contains 5 red balls and 4 black balls,Urn C contains 4 red balls and 4 black balls.One ball is drawn from each of these urns.What is the probability that 3 balls drawn consist of 2 red balls and a black ball??

• A B C
  R R B
  B R R
  R B R
  so,prob=(4/7*5/9*4/8)+(3/7*5/9*4/8)+(4/7*4/9*4/8)
  =17/42
  
• 12 years agoHelpfull: Yes(36) No(1)
• { C(4,1)/C(7,1) x C(5,1)/C(9,1) x C(4,1)/C(8,1) } + { C(4,1)/C(7,1) x C(4,1)/C(9,1) x C(4,1)/C(8,1) } + { C(3,1)/C(7,1) x C(5,1)/C(9,1) x C(4,1)/C(8,1)}
  
  on solving answer is 17/42
• 12 years agoHelpfull: Yes(7) No(2)
• totel ways we can draw 3 balls one from each is 7c1*9c1*8c1=7*9*8
  A B C
  R R B
  B R R
  R B R
  so totel ways to draw two red and one black ball is=
  (4c1*5c1*4c1)+(5c1*4c1*3c1)+(4c1*4c1*4c1)=80+60+64=204
  probability=204/7*9*8=17/42
• 12 years agoHelpfull: Yes(6) No(1)
• how it comes...will u plz explain it properly
  
• 12 years agoHelpfull: Yes(3) No(0)
• ans is ....17/42 ....
  
• 12 years agoHelpfull: Yes(3) No(1)