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?
Options
1) 10/21
2) 11/21
3) 2/7
4) 5/7

• In 60 min , min hand moves by 360 deg and hour hand moves by 30 deg.
  
  After 60 min diff in angles = 360-30 = 330 deg.
  
  For meeting again, diff of angles should be 360 deg.
  
  Angle will be 360 deg after 360*60/330 = 720/11 min from 12O'clock
  i.e. after 65 5/11 mins
• 13 years agoHelpfull: Yes(21) No(5)
• total no of possible event=n(E)=7c2=21
  ball is drawn either red or blue then possible outcomes =n(p)=(2c1*3c1+2c2+3c2)=10
  probability p(E)=n(p)/n(E)=10/21ans.
• 9 years agoHelpfull: Yes(9) No(0)
• Total number of balls=2+3+2=7. Number of ways of drawing 2balls out of 7=7C2=21. Number of ways of drawing 2(blue) ball out of(2+3) balls. =5C2=10. Therefore, none of ball drawn blue=10/21
• 8 years agoHelpfull: Yes(5) No(0)
• @ sanjana,
  I do not think that such qn will be asked here.
  In that case, the two clocks are always matching even after 1 millisecond.
  
  But your observation is correct. I think the question is incomplete.
• 13 years agoHelpfull: Yes(3) No(5)
• It is not about the two hands of the clock
  It is about two clocks. So they meet the next second again
• 13 years agoHelpfull: Yes(2) No(14)
• M=minuts,H=Hours
  our formula for calculating angle between any hands i.e (11/2)*M-30*H
  now both hands are meet together means 0degree or 360 degree
  so
  given H=12
  (11/2)*M-30*12=0
  M=720/11 i.e 65 5/11 minuts after means 1 hr 26/5 minuts
  
• 10 years agoHelpfull: Yes(2) No(0)
• As none of the ball is blue so, 2 red and 3 green will be considered
  so tot =5ball and no. of ball needed to be selected is 2 from 5
  so (5c2) / 7c2(tot)
  =10/21
• 7 years agoHelpfull: Yes(1) No(0)
• total balls 7c2=21 select two balls none of them is blue so 2c1*3c1+2c2*3c0+3c2*2c0=15 finally 15/21=5/7
• 7 years agoHelpfull: Yes(1) No(0)
• Ans:11/21
  Total- none
  1-5c2/7c2
• 6 years agoHelpfull: Yes(0) No(1)