20 passengers are to travel by a doubled decked bus which can accommodate 13 in the upper deck and 7 in the lower deck. The number of ways that they can be distributed if 5 refuse to sit in the upper deck and 8 refuse to sit in the lower deck is:plz solve it asap..

• people refused to sit on upperdeck=5
  " " " " " lowerdeck=8
  other people=7
  first place the 8 members on the upperdeck remaining(13-8=5 places on upperdeck)can be selected in 7c5 ways
  place the remaining people on lower deck(7)
  number of ways=7c5=21
• 9 years agoHelpfull: Yes(5) No(1)
• 20 person are total. There are 5 person refused to sit in upper deck. So we have 15c13(as there 13 can accomodate)
  Similarly 8 person refused to sit in lower deck , so 12c7.
  Total no. Of ways =15c13*12c7.
• 9 years agoHelpfull: Yes(4) No(6)
• refused to sit on upperdeck --->5
  refused to sit on lowerdeck --->8
  total people remaining to arrange is = 20-13=7
  remaining place in upper deck = 5
  therefore, no. of ways possible= 7c5 = 21
  remaining place in lower deck = 2
  therefore, no. of ways possible= 7c2 = 21,also
  no. of ways possible is 21.
  
• 9 years agoHelpfull: Yes(4) No(0)
• Upper desk remain 5 and lower desk 2...
  So total 7.....
  7*6*5*4*3*2*1
• 9 years agoHelpfull: Yes(1) No(0)
• 13860
  12c7 x 15c13
• 9 years agoHelpfull: Yes(0) No(5)
• 5!*2*7*13 = 21840
• 9 years agoHelpfull: Yes(0) No(1)
• 0.33 is correct
• 9 years agoHelpfull: Yes(0) No(4)
• 15C13*12C7=83160
  
• 9 years agoHelpfull: Yes(0) No(3)
• 7c5*13!*7!
  
• 9 years agoHelpfull: Yes(0) No(0)