Mr &mrs smith have invited 9 of their friends & their spouses for a party at the waikki beach resort.they started for a group photograph.if Mr.smith never stands next to mrs smith(as he says they are always together otherwise).how many ways the group can be arranged in a row for the photograph?

• ITS 19!x18...
  
  9 FRIENDS + THEIR SPOUSES = 18 PERSONS
  TOTAL NO OF WAYS IN WHICH 20 PEOPLE (18 + MR & MRS SMITH) CAN ARRANGE THEMSELVES = 20!
  MR & MRS SMITH WILL STAND TOGETHER IN 2x19! WAYS
  Mr & MRS SMITH WILL NOT STAND TOGHETHER IN (20!-19!x2) ways = (20x19!-19!x2) =19!(18)
  
  
• 11 years agoHelpfull: Yes(5) No(1)
• Let take mr and mrs smith together so they become 1 person.
  So total members are 10. They can arange in 10 ways.=3628800.
  But there are actualy 11 members.so they can be arange as in 11 ways=39916800.
  No. of ways they can take their photographs=39916800-3628800=36288000.
  Ans:36288000.
• 11 years agoHelpfull: Yes(0) No(6)