find the no of 6-digit numbers that can be formed using the digits 1,2,3,4,5,6 once such that the 6-digit nos divisible by its unit digit?

• ans 648
  
  If the unit place is 1,2,3,5,6 there are 120 ways to construct 6 digit numbers for each.If the unit digit is 4 then the number of ways is(4*3*2*1*2*1)=48 ways..
  
  So total number of 6 digits formed is(5*120+48)=648
• 9 years agoHelpfull: Yes(22) No(1)
• There are 6 numbers which can be placed in units digits.
  case 1: When the unit digit is 1,2,3,5,6 whatever the other numbers are the 6 digit number will be surely divisible by the unit digit.
  Hence the 5 numbers in the units place can be placed in 5 ways and the remaining 5 numbers can be arranged in 5! ways.
  5*5!=600 ways
  Case 2: If the unit digit is 4, then the tens digit should be 2 or 6, hence 24 or 64 can be arranged in the last two places in 2 ways and the remaining 4 numbers can be arranged in 4 places in 4!ways.
  2*4!=48 ways
  
  
  Total no.of.ways= 600+48 = 648 ways.
• 9 years agoHelpfull: Yes(5) No(0)
• plzz giv correct answer ...
  
• 9 years agoHelpfull: Yes(3) No(0)
• ans 72.
  the units place cant be 1 since all the numbers are divisible by 1
  the units place cant be 2 since all even numbers will be divisible by 2
  the units place cant be 3 since sum of all the digits=21 which is divisible by 3 implying the number is also div by 3
  Similarly the units digit cant be 5 and 6 as well
  So it leaves out only 4
  Now if units place is 4 the tenths place cant be 2 or 6 since 24 or 64 are divisible by 4.So the tenths place can be filled in 3 ways and the rest places in 4! ways.
  Therefore ans is 24*3=72.
  
• 9 years agoHelpfull: Yes(2) No(13)
• There are six numbers which can be placed in unit digit.
  case-1 When the unit digit is 1,2,3,5,6 whatever the other numbers are the 6 digit number will be surely divisible by the unit digit.
  Hence the 5 numbers in the units place can be placed in 5 ways and the remaining 5 numbers can be arranged in 5! ways.
  5*5!=600 ways
  Case 2: If the unit digit is 4, then the tens digit should be 2 or 6, hence 24 or 64 can be arranged in the last two places in 2 ways and the remaining 4 numbers can be arranged in 4 places in 4!ways.
  2*4!=48 ways
  
  
  Total no.of.ways= 600+48 = 648 ways.
• 9 years agoHelpfull: Yes(2) No(0)
• ans 648
  
  if the unit place digit is 1,2,3,5,6 there are 120 ways to costruct 6 digit no for each.if unit digit is 4 then [||||(2,6)|4] the no of ways is 4*3*2*1*2*1=48 ways...
  
• 9 years agoHelpfull: Yes(1) No(2)
• 1,2,3,5 will nt form any no..!!
  bt in d case of 4..it form only those no in which ten digit contain 1,3,5 so no will be 1*2*3*4*3*1=72
  6 will also doesnt form any no..bcz in any case it will divisible by 2*3
• 9 years agoHelpfull: Yes(0) No(9)
• if unit digit is 1 then 5!= 120
  if unit digit is 2 then 5!= 120
  if unit digit is 3 then 5!= 120(sum is 21)
  if unit digit is 5 then 5!= 120
  if unit digit is 6 then 5!= 120
  if unit digit is 4 then 2*4!=48 (24,64 only)
  total = 648
  and we can arrange total in 6!=720 ways
  720-648=72
• 9 years agoHelpfull: Yes(0) No(2)
• Is it 72 or 648 which is correct??????
• 9 years agoHelpfull: Yes(0) No(0)
• 648 is right answer
  
• 8 years agoHelpfull: Yes(0) No(0)