How many 5 digit numbers are possible by using the digits 1, 2, 3, 4, 5 which are divisible by 4 if repetition of digits is allowed?

• answer =625.
  by using 1,2,3,4,5 there are 5 possible combinations of numbers which are divisible by 4 i.e. 12,24,32,44,52.
  so in 5 digits combination first 3 digits doesn't matter hence
  (possible formations divisible by 4)=5
  (fist 3 digits will be of any combination)=(5^3)
  final answer 5*5^3=625 .
• 10 years agoHelpfull: Yes(13) No(3)
• Got the answer!
  if a number is to be divisible by 4,then the condition is the last two digits should b divisible by 4.
  Since in this example,5 digit number is to be formed,
  _ _ _ 12
  _ _ _ 24
  _ _ _ 32
  _ _ _ 44
  _ _ _ 52
  
  So the chances are as above..
  5P5 * 5P5 * 5P5 * 5 since 5 cases are there! i.e 5^4=625 is the answer!
• 10 years agoHelpfull: Yes(7) No(0)
• when unit digit is 2 then 3*2*1*1 and when unti digit is 4 then 3*2*1*2 so,6+12=18
• 10 years agoHelpfull: Yes(0) No(8)
• 625 is the ans
• 10 years agoHelpfull: Yes(0) No(1)
• ans is 625
  
  
• 10 years agoHelpfull: Yes(0) No(0)
• ans is 625
  
  
• 10 years agoHelpfull: Yes(0) No(0)
• no of digits =5; to form 5 possible digits which is n; so use 5^n-1;
  so 5^(5-1)=5^4=625
• 10 years agoHelpfull: Yes(0) No(0)