The citizens of planet nigiet are 9 fingered and have thus developed their decimal system in base 9. A certain street in nigiet contains 100 (in base buildings numbered 1 to 100. How many 3s are used in numbering these buildings?

• Nos having digit 3 are
  3,13,23,30,31,32,33,.....38,43,53,63,73,83,
  9 times at unit place and 9 times at tens place
  
  so total 18 times.
• 12 years agoHelpfull: Yes(3) No(2)
• sorry ans=18
• 12 years agoHelpfull: Yes(2) No(0)
• i think frnz da simple formula for this is (n-1)* base^(n-2) apply here n=3 base=9 ans =9
• 12 years agoHelpfull: Yes(1) No(5)
• Nor Of 3's in unit place.
  3,13,23.......83 -->(9 times)
  Nor of 3's in ten's place(9th place in base 9)
  30,31,32......38--->(9times)
  so total nor of 3's is 9+9=18 times.
• 12 years agoHelpfull: Yes(0) No(0)