In a colony the municipality decided to number the houses and the shops. They want to number the shops with the numbers containing 3 between 1-100. The houses are 10-20 floored and at the back of the houses 8 feet is left for fire exit. How many shops can be numbered?

• 19 shops
  
  3numbers containing 3
  --->3,13,23,... = 10 numbers
  ---->30,31,32... = 10 numbers
  total = 20 -1 = 19 (number 33 is repeated)
• 10 years agoHelpfull: Yes(19) No(7)
• 18 is the ans
  btw 1 to 100 there are 19 no which consist 3
  they are 3,13,23,30,31,32,33,34,35,36,37,38,39,43,53,63,73,83,93
  13 is aloted as a house no so
  no of shops =19-1=18
• 9 years agoHelpfull: Yes(8) No(4)
• Ans:19
  3,30,31,32,33,34,35,36,37,38,39,13,23,43,53,63,73,83,93
  
  33 shld cme two times so ignore one..
• 9 years agoHelpfull: Yes(2) No(1)
• numbers containing 3 are 3, 13, 23, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 43, 53, 63, 73, 83, 93
  total 19
• 9 years agoHelpfull: Yes(0) No(1)
• 2( 30 , 31, 32, 33, 34, 35, 36, 37, 38,39) - 1 = 2*10 - 1= 19
  we multiplied with 2 because we get both pairs e.g: (30 and 03) or (23 and 32) . we deducted 1 because 33 is single .
• 9 years agoHelpfull: Yes(0) No(0)