A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?
a)10/21
b)11/21
c)2/7
d)5/7

• probability that none of the balls drawn is blue = (5/7) *(4/6) = 10/21 ..... option a)
• 13 years agoHelpfull: Yes(7) No(15)
• (5c2)/(7c2)= 10/21
  
• 10 years agoHelpfull: Yes(2) No(4)
• total no of balls drawn at random=2c2+3c2+2c2=7
  taken two balls are none of balls drawn is blue=2c2*3c2*2c2-2c2=1*3*1-1=3-1=2
  so p=except blue ball/tot no of balls=2/7
• 7 years agoHelpfull: Yes(0) No(2)
• (5c2)/(7c2)=10/21 (answer)
  7c2 because 2 balls are drawn from 7 balls.
  now the question says that drawn balls are not from blue...so we neglect blue balls...
  Now remaining are 2 red and 3 green balls ...in which we have to select 2 balls..
  therefore it will be done by 5c2 way...(2 red + 3 green)
• 5 years agoHelpfull: Yes(0) No(0)