3 PERSONS IS TO BE SEATED IN 9 SEATS SUCH THAT NO ONE SEAT ADGACENT TO EACH OTHER.HOW MANY WAY????

• place 3 to people to either odd places or at even places...
  for odd places...5C3*fact3=60
  for even places...4C3*fact3=24
  so total ways=60+24=84
• 10 years agoHelpfull: Yes(36) No(12)
• 9-(3-1)=7
  7c3=35
  35*3!=210
• 10 years agoHelpfull: Yes(7) No(10)
• Total no of ways of sitting for 3 people=9c3=84;
  Total no of ways in which they sear together= 7;
  
  So, no of ways in which they do not seat together=84-7=77.
• 10 years agoHelpfull: Yes(3) No(7)
• 9C3-(7C1+8C2) = 84-(7+28) = 49
  9C3=total no. of ways three persons can be seated in 9 seats.
  7C1=total no. of ways three persons can be seated in 9 seats such that all three are always together.
  8C2=total no. of ways three persons can be seated in 9 seats such that any 2 are always together.
• 10 years agoHelpfull: Yes(3) No(6)
• 3 persons can be seated in 9c3 ways = 84 ways.
  ways in which they are seated together= 7 ways
  
  total number of ways== 77 ways. :)
  
• 10 years agoHelpfull: Yes(2) No(4)
• arun we should consider 2 adjacent also
  
• 10 years agoHelpfull: Yes(2) No(0)
• 1-(3!*3!*3!)=215 is the ANSWER
  
• 10 years agoHelpfull: Yes(0) No(6)
• 9*7*5
  =315
• 10 years agoHelpfull: Yes(0) No(9)
• 9c3*3!-7*3!-8*2!=504-42-32=430
• 10 years agoHelpfull: Yes(0) No(2)
• forward condition:
  p_p_p_p_ _=4!(4 person arrangement so 4!)
  p_ _ p_p_p_=4!(4 person arrangement so 4!)
  p _ _ _p_p_p=4!(4 person arrangement so 4!)
  
  reverse condition:
  _ _ p_ p_ p_ p=4!(4 person arrangement so 4!)
  _ p_ p_ p_ _p=4!(4 person arrangement so 4!)
  p _ p_ p_ _ _p=4!(4 person arrangement so 4!)
  
  and there is no person in edges:
  _p_p_p_p_=4!(4 person arrangement so 4!)
  
  so answer is 4!+4!+4!+4!+4!+4!+4!=7*24=168
• 9 years agoHelpfull: Yes(0) No(0)