A bag contains 4 red, 5 green and 7 blue balls. Two
balls are drawn at random. What is the probability
that one is green and second of the balls drawn is
blue?
(1)10/11 (2)11/21 (3)35/128
(4)5/76 (5)None of these

• total outcomes = 16c2.
  probability of 1 ball is green and 2nd ball is blue is=5c1*7c1/16c2=5*7/8*15=7/24
  so ans is (5)none of these
• 8 years agoHelpfull: Yes(8) No(0)
• 3). (4c1*7c1)/(16c2) = 35/128
• 8 years agoHelpfull: Yes(2) No(8)
• (5).
  probability of one ball green and second ball blue is (4c1/16C1)*(7c1/15C1).
• 8 years agoHelpfull: Yes(0) No(5)
• Total 2 balls are drawn so its probability is 16C2 ( 16 because there are total 16 balls)
  
  Now probability that 1st one is green is 5C1 ( as it is asked for 1st ball to be green we will choose only from green balls)
  
  and 2nd ball to be blue probability is 7C1( as 7 blue balls r there)
  now total probability will be (5C1+7C1)/16C2
  
  => 12/120
  =>1/10
  so reqiured ans must be 1/10
  
  
• 8 years agoHelpfull: Yes(0) No(5)