Latest TCS Aptitude Question SOLUTION: 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? a. 18

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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?
a. 18!x2

b. 17!
c. 17x2!

d. 12

Asked In TCS milan jena (8 years ago)

Solved palak Read Solution (19)

Is this Puzzle helpful?   (67)   (12) Submit Your Solution Permutation and Combination

Read Solution (19) :

palak  (8 years ago) Best Solution

Now the first sister can sit in 20 ways and other sister can sit either left or right such that 2 ways .All men can sit in remaning 18 seats i.e 18!
Answer is 18!x2

Is this solution Helpfull? Yes (33) | No (5)  

Deepesh Malviya  (8 years ago)

Here 2 sisters can be assumed 1 sister,
In this way there are total of 19 member,
Formula for circular seating arrangement: (n-1)!
So, (19-1)! = 18!
But 2 sisters can also sit in 2 ways,
Hence answer is 18! *2

Is this solution Helpfull? Yes (19) | No   

Shana Hermiya  (8 years ago)

Ans is: 17!*2!
formula for circular arrangement: (n-1)!
so, for 18 men arrangement: (18-1)!=17!
18 men and 2 sisters arrangement = 17!*2!

Is this solution Helpfull? Yes (8) | No (16)  

pooja kumari  (8 years ago)

option A is the right answer

Is this solution Helpfull? Yes (6) | No   

PRASHANT TAYAL  (8 years ago)

Answer is 18!*2
The two girls can be arranged between 18 Men in 18! ways.
Ad there positions can also be interchanged.
So total ways are 18!*2

Is this solution Helpfull? Yes (6) | No (2)  

hema chandra  (8 years ago)

first learn this question thoroughly here they asked for no of arrangements not for probability so first given data is:
18m and 2sis ,take 2 sisters as one unit such that they are total of 19units which as byformula
(n-1)!therefore (19-1)!*2! =18!*2 (2! is such that 2 sisters can be arranged among them selves seperated from man in 2!ways)

Is this solution Helpfull? Yes (3) | No   

Javed  (7 years ago)

since two sisters are always separated by one man so fix these three ( two sisters and a man in middle), now 17 man are left which can be arranged in 17! ways and two sisters can be arranged around the man in 2 ways.
so, total no of arrangements = 17! * 2

Is this solution Helpfull? Yes (3) | No (1)  

anjali gupta  (8 years ago)

17!*2
consider the circle=(n-1)!

Is this solution Helpfull? Yes (2) | No (2)  

bhupendra  (8 years ago)

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

Is this solution Helpfull? Yes (1) | No (1)  

Abhishek kumar  (8 years ago)

answer should be A.because here not talking about men.
so men are sitting in !18 AND two sister in 2! ways

Is this solution Helpfull? Yes (1) | No   

Deepalakshmi  (8 years ago)

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

Is this solution Helpfull? Yes (1) | No   

ROZINA KHATUN  (7 years ago)

First 18 men can sit to the table in (18-1)! ways that means 17! ways and the remaning places 2 can be arrange by two girls in 2p2 ways=2! ways.so the answer is 17!*2! i.e, 17!*2 ways.so the option c is the right answer

Is this solution Helpfull? Yes (1) | No   

jahnaviMoparthi  (6 years ago)

18!*2
s-m-s one set
rem 17+one set=18
circle=17!
men=18
17!*18*2=18!*2

Is this solution Helpfull? Yes (1) | No (1)  

shifa shaikh  (8 years ago)

a.probablity

Is this solution Helpfull? Yes | No (1)  

Ashish bhangade  (8 years ago)

18!*2
Because 18 Not multiple of 2
2 is sisters are women it is not include in men.

Is this solution Helpfull? Yes | No   

srini  (7 years ago)

Ans a because of 18 members sitting

Is this solution Helpfull? Yes | No   

prakshi gupta  (7 years ago)

two sisters asssumed one unit so total no. of ways=19
so no. of arrangements=18!
so answer is 18!*2

Is this solution Helpfull? Yes | No   

oviya  (7 years ago)

nithiya 758b 3456

Is this solution Helpfull? Yes | No   

salman khan  (6 years ago)

assume that one seat consider as sister1 men sister2 and remaining seat are 17 seats so, total seat are 18
seating arrangement are 18! and both sisters can exchange their position in 2 ways then
the answer is 18!*2

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