How many 6 digits number can be formed using the digits 1 to 6,without repetition such that the number is divisible by the digit at its unit place?

(A)402
(b)528
(c)648
(d)720

• the numbers will end with 1,2,3,4,5,6
  the numbers made with last digit as 1 is
  5*4*3*2*1=120
  similarly for 6 digits is
  120*6=720
  but in case of 4 the number is not divisible when it is 14,34,54
  those combinations are 4*3*2*1=24*3=72(bcoz 14,34,54 (3) combinations)
  720-72=648
• 10 years agoHelpfull: Yes(15) No(6)