find the number of 6 digit numbers that can be formed using digits 1,2,3,4,5,6 once such that the 6digit number is divisible by its unit digit.

• Answer is 648.
  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.
• 10 years agoHelpfull: Yes(72) No(8)
• when unit digit 1,2,3,5,6 then no. formed will be divisible by the digit at the unit place.
  => 5*5p5 numbers
  
  when unit place is 4, tenth place should be 2 or 6
  => 2*4p4 numbers
  
  total = 5*5p5 + 2*4p4 = 5*5! + 2*4! = 648
  
• 10 years agoHelpfull: Yes(23) No(5)
• Ans:528
  Digits 1,2,3,4,5,6
  When unit digit is 2,3,4,5,6
  When unit digit is 2 it is divisible 2
  5!=120
  When unit digit is 3 it is divisible 3
  5!=120
  Similarly for unit digit 5 and 6
  the number of required numbers is 120 each
  When unit digit is 4 it is divisible by both 2 and 6
  2*4!=48
  Total=4*120+48=480+48=528 is Ans
• 10 years agoHelpfull: Yes(9) No(18)
• 5*5!+2*4!
  =648
• 10 years agoHelpfull: Yes(3) No(5)
• Ans:528
  Digits 1,2,3,4,5,6
  When unit digit is 2,3,4,5,6
  When unit digit is 2 it is divisible 2
  5!=120
  When unit digit is 3 it is divisible 3
  5!=120
  When unit digit is 3 it is divisible 3
  5!=120
  Similarly for unit digit 5 and 6
  the number of required numbers is 120 each
  When unit digit is 4 it is divisible by both 2 and 6
  2*4!=48
  Total=4*120+48=480+48=528 is Ans
• 10 years agoHelpfull: Yes(2) No(19)
• 720
  6 digits numbers can be formed i.e 6!=6*5*4*3*2*1=720
• 10 years agoHelpfull: Yes(1) No(2)
• 528 is right answer.....its cat quant.(permutaion &combination) level 1(q-59)
• 9 years agoHelpfull: Yes(1) No(0)
• unit digit no of possibilites
  1 5!
  2 5!
  3 5!
  4 4!*7
  5 5!
  6 5!
  total no possibilities 5*5!+4!*7=768
• 10 years agoHelpfull: Yes(0) No(6)
• according to me ans is 648.
• 10 years agoHelpfull: Yes(0) No(2)
• 5!*5=600
  4!+4!+600= 648 ans
• 10 years agoHelpfull: Yes(0) No(2)
• when the unit digit is 1,2,3,5,6 the remaining digits will be divided by them so 120+120+120+120+120
  when unit digit is 4 then its corresponding tens digit must be 2 or 4 so it can be arranged in 2*4! ways so total is 600+48=648 ways
  
• 10 years agoHelpfull: Yes(0) No(1)