How many four-digit no. contain the digits 3 or 6.

• total no of 4 digit nos are 9*10*10*10=9000
  no of 4 digit nos that dont contain 3 or 6 are 7*8*8*8=3584
  so 4 digit nos that contain 3 or 6 are 9000-3584=5416
• 10 years agoHelpfull: Yes(42) No(3)
• ways of arranging 3 at 4 places = 4! = 24
  ways of arranging 6 at 4 places = 4! = 24
  ways of arranging 3 or 6 at 4 places = 24 + 24 = 48
• 10 years agoHelpfull: Yes(6) No(12)
• total number of 4 digit=9000
  total numbers of 4 digit without containig digit 3 and 6=7*8*8*8=3584
  so total numbers of 4 digit containg digit 3 or 6=9000-3584=5416
• 9 years agoHelpfull: Yes(5) No(0)
• for 3
  in unit place> 3
  in tenth place> 33
  in hundred place> 333
  in thousand place> 3333
  3+33+333+3333=3707
  
  for 6
  similar 6+66+666+6666=1157
  
  add these two 3707+7407= 11114
• 10 years agoHelpfull: Yes(1) No(14)
• Ans: 4450
  We have 35 no.s from 1000 to 1100 with digits 3 or 4. Similarly, same for 1100 to 1200, 1200 to 1300 n so on upto 2000 excluding 1300 to 1400 and 1600 to 1700. In these two series we have 100 in each. So from 1000 to 2000 we have 35*7+100*2=445. Hence all four digits we get 445*10=4450.
• 10 years agoHelpfull: Yes(0) No(2)
• 4 digit no: 1st 2nd 3rd 4th positions
  At the 1st position 0,3,6 are not allowed so we can fill it with remaining 7 digits.
  At 2nd position (10 digits -3,6=8) similarly for 3rd,4th position.
  Hence ans is : 7*8*8*8=3584
  
• 9 years agoHelpfull: Yes(0) No(2)
• can any explain clearly how 8 & 7 came..........
• 9 years agoHelpfull: Yes(0) No(1)