How many 4 digits number contain the number 2.

a) 3170
b)3172
c)3174
d)3168

• option d.
  total no. of 4 digit nos are 9000(btwn 1000 and 9999).
  consider the case where the nos contain no 2 in it.
  so units place can be filled in 9 ways(0,1,3,4,5,6,7,8,9)
  smlry,tenths place in 9 ways
  hunderedths place in 9 ways
  thousands place can be filled in 8 ways only(because 0 cannot come)
  so total nos are (9000-(8*9*9*9))=3168
• 10 years agoHelpfull: Yes(57) No(1)
• 9*10*10*10-8*9*9*9=3168
• 10 years agoHelpfull: Yes(11) No(1)
• Total number of four digit numbers =9000 ( 1000 to 9999 )
  the units place it can be selected in 9 ways ( 0,1,3,4,5,6,7,8,9)
  Tens place it can be selected in 9 ways ( 0,1,3,4,5,6,7,8,9)
  Hundreds place it can be selected in 9 ways ( 0,1,3,4,5,6,7,8,9)
  Thousands place can be selected in 8 ways ( 1,3,4,5,6,7,8,9) here 0 cannot be taken
  Total number of numbers not having digit 2 in it =9 x 9 x 9 x 8 =5832
  Total number of numbers having digit 2 in it = 9000-5832 =3168
• 10 years agoHelpfull: Yes(2) No(0)
• Total number of four digit numbers =9000 ( 1000 to 9999 )
  the units place it can be selected in 9 ways ( 0,1,3,4,5,6,7,8,9)
  Tens place it can be selected in 9 ways ( 0,1,3,4,5,6,7,8,9)
  Hundreds place it can be selected in 9 ways ( 0,1,3,4,5,6,7,8,9)
  Thousands place can be selected in 8 ways ( 1,3,4,5,6,7,8,9) here 0 cannot be taken
  Total number of numbers not having digit 2 in it =9 x 9 x 9 x 8 =5832
  Total number of numbers having digit 2 in it = 9000-5832 =3168
  Read more at http://www.m4maths.com/placement-puzzles.php?ISSOLVED=&page=2&LPP=10&SOURCE=TCS&MYPUZZLE=&UID=&TOPIC=Numerical%20Ability&SUB_TOPIC=Number%20System#G6reJpBimqf3MmoK.99
• 10 years agoHelpfull: Yes(0) No(0)