There are 20 persons sitting in a circle. In that, there are
18 men and 2 sisters. How many arrangements are possible,
in which the two sisters are always separated by a man?

• consider the two sisters and a man together as 1 unit
  now total left person are 17
  and we will add the 1for two sisters and a man combination
  so total 18 people now they can be arranged in 18! ways
  two sisters can be interchanged
  so answer will be 18!*2
• 5 years agoHelpfull: Yes(10) No(0)
• Fix the postion of two brothers. This leaves us with 18 people.
  So there 18 ways in which a person can sit between two brother. Now swap thsoe bothers we get another 18 ways
  So combinations = 2 * 18.
  Consider the groupe of three people a single entity
  we have another 17 people left so there are 18 entities to be arranged
  Around a circle. Tis can be done in (18-1)! = 17!
  
  Total no of ways = 2 * 18 * 17! = 2 * 18!
• 5 years agoHelpfull: Yes(4) No(0)
• 2 sister can be seat in 2 ways.
  18 persons seat in 18! Ways
  Ans 2*18!
• 5 years agoHelpfull: Yes(3) No(0)
• Total possible ways = 20!
  Two sisters always sitting "TOGETHER" possible ways = 19!*2
  So therefore as given two sisters always separated by a man is = 20! - (19!*2)
  =18 * 19! ways
• 5 years agoHelpfull: Yes(1) No(1)
• Let us consider the 2 sister be 1 unit and 18 men as 18 units.
  In circular permutations, n units can be arranged in (n-1)! ways.
  So, 18 units of men + 1 unit of sisters can be arranged in 18! ways and both the sisters can be arranged among themselves.
  Therefore, the no. of arrangements are
  19! -18! 2! = 18! (19-2) = 17*18!
• 4 years agoHelpfull: Yes(1) No(0)
• Since 2 sisters in between a man can be arranged in 2*18 ways.
  And now the remaining people will be 17 + the sisters combination = 18
  All together consider as 18 people and these 18 people can be arranged in 18-1!
  i.e, 17! * 2 * 18
• 5 years agoHelpfull: Yes(0) No(1)
• ans:18!x2!
  
  posibility of 18 people arrange the order is -18!
  two sister arrange the order-2!
  so answer is -18!x2!
• 5 years agoHelpfull: Yes(0) No(1)
• 2*18!
  fix two sisters in a position.So the remaining 18 males can sit in 18! ways
• 5 years agoHelpfull: Yes(0) No(0)
• Let the first sister name is A. Now she can sit any where in the 20 places (Symmetrical). Now her sister B can sit to her left or right in 2 ways. Now the remaining 18 persons can be sit in 18 places in 18! ways. Total = 18! * 2
• 5 years agoHelpfull: Yes(0) No(0)
• 18 members can be arranged in (18-1)!
  2 females can arranged in 2 ways
  selection of one male candidate 18c1
  ans is 18*17!*2
• 5 years agoHelpfull: Yes(0) No(0)
• 18! for men
  total:18!*17*16
• 5 years agoHelpfull: Yes(0) No(1)