In a class, seven students P, Q, R, S, T, N and O are standing in a row from left to right. Q is standing to the left of R but to the right of P. O is standing to the right of N but to the left of P. S is standing to the right of R but to the left of T. Who is standing exactly in the middle position of this row of seven students?

Introduction / Context:
This question involves arranging several students in a single row based on relative position clues. Each clue gives a partial ordering between some of the students, and you must combine all of them to obtain a single consistent order from left to right. Once the order is known, identifying the middle position is straightforward. Problems of this type strengthen logical deduction and ordering skills.

Given Data / Assumptions:

• Seven students P, Q, R, S, T, N and O stand in one row from left to right.
• Q is to the left of R and to the right of P, so P < Q < R in positional order.
• O is to the right of N and to the left of P, so N < O < P.
• S is to the right of R and to the left of T, so R < S < T.
• All seven names must appear exactly once in the row.

Concept / Approach:
The approach is to convert each statement into an inequality involving positions, then combine these inequalities into a single chain. Each relation tells us how two or three students are ordered relative to each other. If no contradictions arise, we obtain a unique linear order. Since there are seven students, the middle position is the 4th position from the left. The student at this position is the answer.

Step-by-Step Solution:
From “Q is to the left of R but to the right of P”, we have P < Q < R. From “O is to the right of N and to the left of P”, we get N < O < P. From “S is to the right of R and to the left of T”, we get R < S < T. Combine the chains. From N < O < P and P < Q < R, we get N < O < P < Q < R. Further combining R < S < T, the full chain becomes N < O < P < Q < R < S < T. Thus, in the row from left to right, the order of students is N, O, P, Q, R, S, T. Since there are seven students, the middle position is the 4th from the left. The student at position 4 in this order is Q.

Verification / Alternative check:
Check each clue against the order N O P Q R S T. Q is right of P and left of R, so P Q R appears correctly. O is right of N and left of P, so N O P is correct. S is right of R and left of T, so R S T is correctly placed. All conditions are satisfied with no conflicts. Counting positions, we have position 1: N, 2: O, 3: P, 4: Q, 5: R, 6: S, 7: T. Therefore, Q is unquestionably at the central, 4th position.

Why Other Options Are Wrong:
R stands at position 5, not in the middle. P stands at position 3, left of the middle. S stands at position 6, and O at position 2. None of these are in the 4th position. Only Q occupies the exact middle position in the row.

Common Pitfalls:
A common mistake is to misread the direction of inequalities, for example placing Q on the left of P instead of the right. Another pitfall is to try to fix positions too early without merging all chains, which can result in contradictions later. Some candidates also confuse “middle” with an average of positions without counting carefully. Always form one complete order, then explicitly count positions from left to right to identify the central student.

Final Answer:
The student standing in the middle position of the row is Q.