A certain street contains 100 buildings.
They are numbered from 1 to 100. How many 9s are used in numbering these buildings?

21
20
19
9

• in first 100 numbers every digit from 1 to 9 is used 20 times.
  
  Hence 9 is used 20 times.
• 12 years agoHelpfull: Yes(4) No(1)
• Answer is = 20
  Expl: Using of 9's from 1-100 is = 9,19,29,39,49,59,69,79,89,90,91,92,93,94,95,96,97,98,""99"(it having two 9's)"is equal to 20
  
• 12 years agoHelpfull: Yes(4) No(0)
• 9s are used 20 times in numbers from 1 to 100. It can be counted as below
  9,19,29,39,49,59,69,79,89,90,91,92,93,94,95,96,97,98,99
• 12 years agoHelpfull: Yes(2) No(0)
• numbers given to buildings(9,19,29,39,49,59,69,79,89,90,91,92,93,94,95,96,97,98,99)
  by counting no. of nines we get 19
  so ans=20
• 12 years agoHelpfull: Yes(2) No(1)
• numbers given to buildings(9,19,29,39,49,59,69,79,89,90,91,92,93,94,95,96,97,98,99)
  by counting no. of nines we get 19
  so ans=19
• 12 years agoHelpfull: Yes(0) No(9)
• 2*9=18
  nearest is 19
• 11 years agoHelpfull: Yes(0) No(0)