How many 9 digit numbers are possible by using digits 1,2,3,4,5 which are divisible by 4 if the repetition is allowed?
a.5^7 b.5^6 c.5^9 d.5^8

• i cant understand how this optins are possible......
  
  anyway,the rule is any number divisible by 4 and constructed by 1,2,3,4,5 must have the last digits as 12,24,32,44,52.
  so the last two digits can be any of these 5s
  and the remaining 7 digits can be formed using 1,2,3,4,5 in any way
  so 5*5*5*5*5*5*5*5(the last five is for the last two digits).
• 13 years agoHelpfull: Yes(7) No(2)
• ya moumita is correct..option should be 5^8...not 58..
• 13 years agoHelpfull: Yes(4) No(2)
• the options are incorrect
  the answer wull be=5*5*5*5*5*5*5*5
• 13 years agoHelpfull: Yes(2) No(1)