## SIG (Susquehanna International Group) Interview Question for Analysts

Country: United States

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6
of 6 vote

Imagine that each seat around the round table is numbered 1,2,..,5
Imagine that each person is numbered 1,2,...,5 according to their age-rank.

There are 5 ways that the 5 people can be seated in ascending-age order.
There are 5 ways that the 5 people can be seated in descending-age order.
There are 5! different ways the people can be seated in general

So, the probability of a successful arrangement is (5+5)/5! or 1/12

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0

Ty for the answer. I was wondering why you have not considered that they might be sitting in anti clockwise direction as well ? The above answer will apply even if we speak of a straight table. But its a round table...Can anyone help here..? My answer is also coming 1/12 using addition theory. :/

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0

what if n=3 ? probability is 1. for n=2, probbility is >1

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1
of 1 vote

I think the total combination number is (n-1)!, because in round table, you should first pin one, then start calculate the number of combinations. The it is 1/(n-1)!=1/4!.

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1
of 1 vote

Its 2 / (5-1)! = 1/12, and yes i am certain of it.

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0
of 0 vote

Total no.of ways in which 5 people can be arranged around a table (N)= 5!/2
No.of favorable ways(P) = 1 (as ascending or descending order around a table is a single arrangement)

Probability = P/N = 2/5!

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0
of 0 vote

Total no of combinations in a round table arrangement = (n-1)!
Ordering we are interested = 2 (PS. Ascending and descending order are different as for a person, the one sitting on left and the one sitting on right will be interchanged when the ordering moves from ascending to descending)

So, probability = 2/(n-1)! = 2/4! = 1/12

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0
of 0 vote

assuming the cont happens only in one direction either clockwise or anti.
the first person with least age can select any of the 5 available seats.next person has only one way ans so on upto 5th person.
Same for descending there are 5 ways.
so total is 10 ways
the no of total ways is 5! as we are counting only in one direction.

so probability is 10/5!

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0
of 0 vote

Very easy questions.

We fix a place where the person with the lowest age sits.
Now, the probability that the person with the second lowest age sits either to his left = (number of seats he can sit on / total number of seats left) = 1/4.
The probability that the person with the third lowest age sits two seats left of the person with the lowest age = 1/3 since there are 3 seats left.
Similarly, probability that next person sits in the right place is 1/2.
After this, the 5th person only has one seat to sit on.

So the probability of all these events happening together = 1/2 * 1/3 * 1/4 = 1/24.

Now the same arrangement could happen towards the right (opposite direction). Either of the arrangements is possible.
So total probability = 1/24 * 2 = 1/12.

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0
of 0 vote

P = P_valid / P_all

P_all = 5!, there is 5! possibilities how to order five people.

P_valid = 5 + 5, five descending (because we are not interested, where theoldest person is siting) and five descending.

Thus, P = 10 / 5!

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0
of 0 vote

correct...
generally we forget the case that in round table
12345
23451
34512
45123
512345
all are ASC order sitting arrangement same we can get in DESC order.

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0
of 0 vote

answer is 0. if members are seated at a round table than a there is not a specific descending or ascending order. The eldest and youngest individuals will be always be seated next to one another, in a dickhead kind of way of thinking about the question.

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0
of 0 vote

answer is 0. if members are seated at a round table than a there is not a specific descending or ascending order. The eldest and youngest individuals will be always be seated next to one another, in a dickhead kind of way of thinking about the question.

Comment hidden because of low score. Click to expand.
0
of 0 vote

answer is 0. if members are seated at a round table than a there is not a specific descending or ascending order. The eldest and youngest individuals will be always be seated next to one another, in a dickhead kind of way of thinking about the question.

Comment hidden because of low score. Click to expand.
0
of 0 vote

answer is 0. if members are seated at a round table than a there is not a specific descending or ascending order. The eldest and youngest individuals will be always be seated next to one another, in a dickhead kind of way of thinking about the question.

Comment hidden because of low score. Click to expand.
0
of 0 vote

answer is 0. if members are seated at a round table than a there is not a specific descending or ascending order. The eldest and youngest individuals will be always be seated next to one another, in a dickhead kind of way of thinking about the question.

Comment hidden because of low score. Click to expand.
0
of 0 vote

answer is 0. if members are seated at a round table than a there is not a specific descending or ascending order. The eldest and youngest individuals will be always be seated next to one another, in a dickhead kind of way of thinking about the question.

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0
of 0 vote

that_guy is real dick head in terms of posting the wrong answer with so much guts!

The answer is 2/ (4!) = 1/12.

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0
of 0 vote

Let the people be A, B, C, D, E in order of age.

A can sit anywhere, so he sits "correctly" with probability 1.
B has to sit to A's immediate left or right for things to work, so this happens with probability 2/4 = 1/2 (of 4 remaining seats)
C has to sit next to B, with probability 1/3 (of 3 remaining seats).
D has to sit next to C, with probability 1/2 (of 2 remaining seats)
E sits in the last remaining spot with probability 1.

Therefore the total probability is 1*1/2*1/3*1/2*1 = 1/12.

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0
of 0 vote

I think that the total number of ways in which they can sit is = 5c1×4c1×3c2×2c1×1c1= 5×4×3×2×1 =120 out of which we have only two ways either ascending or descending so my final answer is 2/120 =1/60

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0
of 0 vote

(n-1)! ways off arrngng n persons in a round table. here it is 4!.
since here there is no diffrence between clockwise order n anticlockwise order, so arrangement would be (n-1)!/2 , i.e 4!/2 = 12.
there is only one way to arrange all people in ascending order(clockwise) which is also a descending order(anticlockwise)
so the probabilty is 1/12.

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0
of 0 vote

5P5 = 120
Seating arrangements 5
so the answer would be 120 / 5 = 24

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