A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9s are used in numbering these buildings?
a.9
b.19
c.20
d.21

• Answer : 20
  Exp: 9,19,29,39,49,59,69,79,89=9
  90,91,92,93,94,95,96,97,98,99=11
  9+11=20
• 10 years agoHelpfull: Yes(16) No(8)
• 20
  
  
  09,19,29,39,49,59,69,79,89,99
  90,91,92,93,94,95,96,97,98
  total nos=20
• 10 years agoHelpfull: Yes(2) No(3)
• 1- 10 only one nine
  similarly for
  11-20,21-30,31-40,41-50,51-60,61-70,71-80,81-89 so total 9 nines b/w 1-89
  n from 90-100 there wud be 11 so 11+9=20
  
• 10 years agoHelpfull: Yes(1) No(5)
• 2o in untis digit 9 then there will be 10 and then when it is at tens digit it will 10 times and at hundredth it is fixed 1 so
  ans is 20
• 10 years agoHelpfull: Yes(0) No(3)