In how many ways can 5 keys be put in a ring?
a)1/2*4!
b)1/2*5!
c)4!
d)5!
e)1/4*2!
f)1/5*2!

• c) 4!
  
  5 keys can be put in a ring in 5!/5 = 4! ways as ring is circular.
  12345 is same as 23451 or 45123.
• 12 years agoHelpfull: Yes(1) No(0)
• According to circular permutation, abcde is same as bcdea and so on..
  so total way = (n-1)!
  ==> (5-1)!
  ==> 4!
• 12 years agoHelpfull: Yes(1) No(0)
• May be 2 x 5!
  
  there are two ends of a ring
  => 2 x 5!
• 12 years agoHelpfull: Yes(0) No(1)
• no of ways to put n keys in the ring =1/2*(n-1)!
  so no of ways to put 5 keys in the ring =1/2*(5-1)!=1/2*4!
• 12 years agoHelpfull: Yes(0) No(1)