If all the odd number from 0 to 10000 were written.How many digits would be written down?

• 1 digit ======> 5
  
  2 digits =====> 45*2 = 90 [11,13,.......,99]
  
  3 digits =====> 450*3 = 1350 [101,103,........,999]
  
  4 digits =====> 4500*4= 18000 [1001,1003,......,9999]
  
  total = 5 + 90 + 1350 + 18000 = 19445
  
• 9 years agoHelpfull: Yes(85) No(5)
• To count number of terms, (l-a)/d +1
  
  so, 1 digit no (1,3,..,9) =>> (9-1)/2 +1 =5
  Consequently no. of digits= 5*1= 5
  
  2 digit no (11,13,....,99) =>> (99-1)/2 +1 =45
  Consequently no. of digits= 45*2= 90
  
  
  3 digit no (101,103,....,999) =>> (999-101)/2 +1 =450
  Consequently no. of digits= 450*3= 1350
  
  4 digit no (1001,1003,....,9999) =>> (9999-1001)/2 +1 =4500
  Consequently no. of digits= 4500*4=18000
  
  So , total no f digits are = 5+90+1350+18000=19445
• 9 years agoHelpfull: Yes(29) No(0)
• 5000 odd numbers
• 9 years agoHelpfull: Yes(3) No(2)
• it asked total digits not total no.
  so p&c used
  
• 9 years agoHelpfull: Yes(2) No(2)
• 19945 same as mentioned
• 9 years agoHelpfull: Yes(2) No(0)
• 5000
  in 10000 every alternate number is odd number so 5000 odd numbers
  
• 9 years agoHelpfull: Yes(1) No(10)
• from
  0 to 10 there will be =5 digits
  11 to 99= 2*45=90
  100 to 999=450*3=1350
  1000 to 9999=4500*4=18000
  total =5+90+1350+18000=19445
• 9 years agoHelpfull: Yes(0) No(1)
• 19445 digits are possible if digits can be repeated
• 9 years agoHelpfull: Yes(0) No(0)
• 49999
  all the alternate number is odd except 0 and 1
  
• 8 years agoHelpfull: Yes(0) No(0)
• correct ans is 5000
  explanation:
  odd no between:
  0 to 10000
  1,3,5,7,9,.......................9999
  a=1,d=2, tn=9999
  we know that
  tn =a+(n-1)d;
  9999=1+(n-1)2
  9998/2=n-1
  4999=n-1
  n=5000
• 8 years agoHelpfull: Yes(0) No(0)
• last term=9999
  a=1,d=2
  l=a+(n-1)d
  9999=1+(n-1)2
  9999-1=2n-2
  9998+2=2n
  n=10000/2=5000
• 7 years agoHelpfull: Yes(0) No(0)
• alternate numberi:e5000
• 7 years agoHelpfull: Yes(0) No(0)
• i think that answer would be 10 because digits from (0-9) is used to form any odd number from 1 to 10000,according to me combination of digits make number.
  for ex.- 121 is a number with 3- digits.
  please review if it seems to be relevant.
• 7 years agoHelpfull: Yes(0) No(0)