three digit number such that two digit is repeated then how many numbers can be formed??

• i thnk the ques was.. find the three digit no. in which atleast 2 digits are same.. then how many numbers can be formed ??
  
  ans is 252
  
  100,101,110,111,112,113,114,115,116,117,118,119,121,122,131,133,141,144,151,155,161,166,171,177,181,188,191,199 =28 no...
  
  so on in series of 200, 300....999
  
  28 *9= 252 is the right ans
• 10 years agoHelpfull: Yes(38) No(3)
• three digit no. repeation allowed is=:9*10*10=900
  three digit no. repeation not allowed=:9*9*8=648
  so only two digit is repeated allowed=:900-648=252(Ans)
• 10 years agoHelpfull: Yes(24) No(0)
• 243 if there only two digit is repeated
• 10 years agoHelpfull: Yes(12) No(5)
• solution can be in 3 ways xxy, yxx and xyx
  so for 1st way i.e xxy permution is 9*1*9=81
  similarly for 2nd nd 3rd way it is also 81
  81*3=243
  ans - 243
• 10 years agoHelpfull: Yes(5) No(1)
• 3 digit number... starting from 100 to 999
  now digit is repeated...
  consider 1 is repeated two times .. 11_ .. we can fill up this black space with 0,2,3....9 if only 2 digit is repeated... so.... 9 possibilities.. 9*3!/2!
  if 2 is repeated two times .. 22_........ so 9*3!/2!
  .
  .
  .total 9*27=243
  and 100,200,300,400,500,600,700,800,900 there are 9 numbers where 0 is repeated 2 times..
  so the ans must be 243+9=252
• 9 years agoHelpfull: Yes(0) No(0)
• Ans : 252
  Sol :
  let the digit is YXX, XXY, XYX
  for YXX : 9*10*1=90
  similar XXY : 9*1*9= 81
  similar XYX : 9*9*1=81
  total : 90+81+81=252
  
• 9 years agoHelpfull: Yes(0) No(0)
• 3 digits no of possibility with repetion allowed => 9*10*10=900
  non repeated no.=> 9*9*8=648
  repeated no.=900-648=252
  3 digit repeat numbrs are 111,222,333,444,555,666,777,888,999
  total no.=9
  final ans=252-9=243
• 9 years agoHelpfull: Yes(0) No(0)
• Ans-243 as 0 is not consider at hundred place and if it is not atleast
• 9 years agoHelpfull: Yes(0) No(0)
• correct answer=252
  consider three digit=a,b ,c
  - - -
  the number we take 0to 9
  if the number is repeated then - - - 1st 2nd 3rd
  1st place take 9
  2nd place take 10
  3rd place take 10
  so total no=9*10*10=900
  if repeatation is not allowed then
  1st place take 9
  2nd place also take 9
  3rd place take 8
  so the 2 digit is same so total no possiblity = reapted no-non repeated no
  900-648=252.
  
  
  
  
  
  
  
  so total no made=9*9*8=648
• 8 years agoHelpfull: Yes(0) No(0)
• 243 is answer
  
  
• 8 years agoHelpfull: Yes(0) No(1)