Practice Test: Seating Arrangement - 1 - UPSC MCQ

Let the people who wear a blue, red and green shirt be denoted by b, r and g respectively. Restrictions on the seating arrangement:
1. Two b’s must not be together.
2. Three r’s must be together.
3. A ‘b’ and a ‘g’ must not be together.
4. A ‘g’ cannot sit on a chair numbered 2 or 9.

Case I: A person wearing a green shirt is sitting on chair numbered 1. It is only possible if another person wearing a green shirt sits on chair numbered 2, but this violates restriction number 4. Hence, this is also not possible.

Case II: A person wearing a blue shirt sits on chair numbered 1. The six seating arrangements that are possible are as follows.

Now, we see that the cases 4, 5 and 6 are just obtained by reversing the cases 1, 2 and 3 respectively. It can be concluded that in any possible seating arrangement, the chairs numbered 1 and 10 are always occupied by people wearing blue shirts. It is given that the number of people wearing a blue shirt is 3. Looking at the table given in the question, we observe that in each of the six arrangements two out of the three different people i.e. A, B and N always sit on chairs numbered 1 and 10.
Hence it can be concluded that the people who wear a blue shirt are A, B and N From the given table the person wearing a blue shirt can never sit on chairs numbered 2, 4, 7 and 9. So, (in arrangement I), A, B and N sitting on chairs numbered 1, 7 and 10 is inconsistent. Also, the people wearing red shirts sit on chairs numbered 2 and 9 and in all the possible arrangements five different people namely P, Q, M, Z and R are sitting on chairs numbered either 2 or 9. Therefore, P, Q, M, Z and R are wearing red shirts and K and L are wearing green shirts. (a) I arrangement is not consistent.

Let the people who wear a blue, red and green shirt be denoted by b, r and g respectively. Restrictions on the seating arrangement:
1. Two b’s must not be together.
2. Three r’s must be together.
3. A ‘b’ and a ‘g’ must not be together.
4. A ‘g’ cannot sit on a chair numbered 2 or 9.

Case I: A person wearing a green shirt is sitting on chair numbered 1. It is only possible if another person wearing a green shirt sits on chair numbered 2, but this violates restriction number 4. Hence, this is also not possible.

Case II: A person wearing a blue shirt sits on chair numbered 1. The six seating arrangements that are possible are as follows.

Now, we see that the cases 4, 5 and 6 are just obtained by reversing the cases 1, 2 and 3 respectively. It can be concluded that in any possible seating arrangement, the chairs numbered 1 and 10 are always occupied by people wearing blue shirts. It is given that the number of people wearing a blue shirt is 3. Looking at the table given in the question, we observe that in each of the six arrangements two out of the three different people i.e. A, B and N always sit on chairs numbered 1 and 10.
Hence it can be concluded that the people who wear a blue shirt are A, B and N From the given table the person wearing a blue shirt can never sit on chairs numbered 2, 4, 7 and 9. So, (in arrangement I), A, B and N sitting on chairs numbered 1, 7 and 10 is inconsistent. Also, the people wearing red shirts sit on chairs numbered 2 and 9 and in all the possible arrangements five different people namely P, Q, M, Z and R are sitting on chairs numbered either 2 or 9. Therefore, P, Q, M, Z and R are wearing red shirts and K and L are wearing green shirts. A, B and N are wearing blue shirts. Hence, N is the answer.

Let the people who wear a blue, red and green shirt be denoted by b, r and g respectively. Restrictions on the seating arrangement:
1. Two b’s must not be together.
2. Three r’s must be together.
3. A ‘b’ and a ‘g’ must not be together.
4. A ‘g’ cannot sit on a chair numbered 2 or 9.

Case I: A person wearing a green shirt is sitting on chair numbered 1. It is only possible if another person wearing a green shirt sits on chair numbered 2, but this violates restriction number 4. Hence, this is also not possible.

Case II: A person wearing a blue shirt sits on chair numbered 1. The six seating arrangements that are possible are as follows.

Now, we see that the cases 4, 5 and 6 are just obtained by reversing the cases 1, 2 and 3 respectively. It can be concluded that in any possible seating arrangement, the chairs numbered 1 and 10 are always occupied by people wearing blue shirts. It is given that the number of people wearing a blue shirt is 3. Looking at the table given in the question, we observe that in each of the six arrangements two out of the three different people i.e. A, B and N always sit on chairs numbered 1 and 10.
Hence it can be concluded that the people who wear a blue shirt are A, B and N From the given table the person wearing a blue shirt can never sit on chairs numbered 2, 4, 7 and 9. So, (in arrangement I), A, B and N sitting on chairs numbered 1, 7 and 10 is inconsistent. Also, the people wearing red shirts sit on chairs numbered 2 and 9 and in all the possible arrangements five different people namely P, Q, M, Z and R are sitting on chairs numbered either 2 or 9. Therefore, P, Q, M, Z and R are wearing red shirts and K and L are wearing green shirts. K and L are wearing green shirts. Hence, K is the answer.

Let the people who wear a blue, red and green shirt be denoted by b, r and g respectively. Restrictions on the seating arrangement:
1. Two b’s must not be together.
2. Three r’s must be together.
3. A ‘b’ and a ‘g’ must not be together.
4. A ‘g’ cannot sit on a chair numbered 2 or 9.

Case I: A person wearing a green shirt is sitting on chair numbered 1. It is only possible if another person wearing a green shirt sits on chair numbered 2, but this violates restriction number 4. Hence, this is also not possible.

Case II: A person wearing a blue shirt sits on chair numbered 1. The six seating arrangements that are possible are as follows.

Now, we see that the cases 4, 5 and 6 are just obtained by reversing the cases 1, 2 and 3 respectively. It can be concluded that in any possible seating arrangement, the chairs numbered 1 and 10 are always occupied by people wearing blue shirts. It is given that the number of people wearing a blue shirt is 3. Looking at the table given in the question, we observe that in each of the six arrangements two out of the three different people i.e. A, B and N always sit on chairs numbered 1 and 10.
Hence it can be concluded that the people who wear a blue shirt are A, B and N From the given table the person wearing a blue shirt can never sit on chairs numbered 2, 4, 7 and 9. So, (in arrangement I), A, B and N sitting on chairs numbered 1, 7 and 10 is inconsistent. Also, the people wearing red shirts sit on chairs numbered 2 and 9 and in all the possible arrangements five different people namely P, Q, M, Z and R are sitting on chairs numbered either 2 or 9. Therefore, P, Q, M, Z and R are wearing red shirts and K and L are wearing green shirts.

Option (1): A (Blue), P (Red), R (Red) and L (Green): Permissible
Option (2): N (Blue), Q (Red), K (Green) and Z (Red): Permissible
Option (3): K (Green), A (Blue), N (Blue) and Z (Red): Not Permissible
Option (4): B (Blue), L (Green), M (Red) and Q (Red): Permissible.

P sits two seats to the left of R, and Q sits two seats to the right of R. We can represent this information in the diagram below.

If S sits between Q and R, then the arrangement is as follows.

As can be seen from the diagram, T is to the immediate right of P. Choice (a)

P sits two seats to the left of R, and Q sits two seats to the right of R. We can represent this information in the diagram below.

We will take each choice and see whether it fits in the arrangement that we represented through a diagram in the analysis of the data (the same diagram is reproduced below).

We can see that the arrangement given in choice (a) is not possible and hence the answer choice is (a).

P sits two seats to the left of R, and Q sits two seats to the right of R. We can represent this information in the diagram below.

If S is not next to Q, then the seating arrangement is fixed as follows.

Now P is between Q and S. Choice (b)

P sits two seats to the left of R, and Q sits two seats to the right of R. We can represent this information in the diagram below.

On the basis of the diagram that we drew, we find that to accommodate U we have to create a new slot between P and Q.

Hence, choice (c) is the correct answer. Choice (c)

P sits two seats to the left of R, and Q sits two seats to the right of R. We can represent this information in the diagram below.

We create a new slot for the sixth person. But since U will not sit next to P, S or T, he will have to sit between R and Q. The arrangement will then look as follows:

As we can see from the diagram, the neighbours of P will be T and S.

Eight persons: P, Q, R, S, T, U, V and W.

1) Three persons sit between S and T.

2) R sits immediate left of T.

3) One person sits between P and Q.

4) Two persons sit between Q and W.

5) V sits immediate left of W.

6) U is not the neighbor of P.

Checking o[tions one by one;

1) Q sits to the immediate right of U → False

2) One person sits between P and R → False

3) Three persons sit between Q and R → False

4) One person sits between S and U → True

Hence, option D is the correct answer.