how many three digit numbers can generated from 1,2,3,4,5,6,7,8,9 such that the digits are in ascending order.
1)80
2)81
3)83
4)84

• 84
  
  Number of Numbers starting with 1 = 7+6+5+..+2+1=28
  Number of Numbers starting with 2 = 6+5+..+2+1=21
  Number of Numbers starting with 3= 5+..+2+1=15
  ..
  ..
  Number of Numbers starting with 7 = 1
  
  Total three digit numbers that can generated from 1,2,3,4,5,6,7,8,9 such that the digits are in ascending order = 28+21+15+10+6+3+1 = 84
• 12 years agoHelpfull: Yes(10) No(2)
• 9*8*7/3!=84
  Possible numbers=84
• 9 years agoHelpfull: Yes(1) No(2)
• 4)84
  9*8*7/3!=504/6=84
• 9 years agoHelpfull: Yes(0) No(2)
• Numbers starting with 1 will be 28....
  with 2 will be 21
  with 3 will be 15
  with 4 will be 10
  with 5 will be 6
  with 6 will be 3
  with 7 will be 1......so the total 84
• 8 years agoHelpfull: Yes(0) No(2)
• 84 9c3..
  Already ascending
• 8 years agoHelpfull: Yes(0) No(1)
• ans-4)84
  count of numbers starting with 1:-7+6+5+4+3+2+1
  {7=count of numbers starting with 12
  6=count of numbers starting with 13
  5=count of numbers starting with 14
  .
  .
  .
  }
  count of numbers starting with 2:-6+5+4+3+2+1
  count of numbers starting with 3:-5+4+3+2+1
  count of numbers starting with 4:-4+3+2+1
  count of numbers starting with 5:-3+2+1
  count of numbers starting with 6:-2+1
  count of numbers starting with 7:1
  
  hence the total count is 84
• 8 years agoHelpfull: Yes(0) No(0)
• 9c3=9*8*7/1*2*3
  =84
  ANS:84
• 8 years agoHelpfull: Yes(0) No(0)
• first place 1 second vary from 2 to 8 and third vari from 3 to 9 total=28
  similary first place 2 second vary form 3 to 8 and third vary form 4 to 9 =21
  15
  10
  6
  3
  1
  total 28+21+15+10+6+3+1=84
• 7 years agoHelpfull: Yes(0) No(0)