P, Q, R, S and T are sitting in a straight line facing north. R is sitting at the extreme left end near the entrance. Q sits next to R. P sits next to S but not next to T. If T does not sit next to Q, then who sits to the immediate left of S?

Introduction / Context:
This is a linear seating arrangement question involving five persons P, Q, R, S and T seated in a straight line facing north. Several relational clues are provided regarding who sits next to whom and where R is located. The task is to use these constraints systematically to determine the unique seating order and then answer who sits to the immediate left of S.

Given Data / Assumptions:

• All five persons sit in a straight line facing north.
• R sits on the entrance left corner, that is, at the extreme left end.
• Q sits next to R.
• P sits next to S but not next to T.
• T does not sit next to Q.
• Left and right are considered from the view of someone facing north.

Concept / Approach:
We treat the five positions from left to right as positions 1 to 5. Since R is at the extreme left end, R must be in position 1. Because Q sits next to R, Q must be in position 2. T cannot sit next to Q, so T cannot be in position 3. We then place P and S so that they sit adjacent to each other and P is not adjacent to T. After all constraints are satisfied, we inspect who is directly to the left of S.

Step-by-Step Solution:
Place R at position 1 (extreme left). Q must sit next to R, so place Q at position 2. T cannot sit next to Q, so T cannot occupy position 3. The remaining positions 3, 4, and 5 must be filled by P, S, and T. P must sit next to S, so they must occupy adjacent positions among 3, 4, and 5. If T were at 4, then P and S would be at 3 and 5, not adjacent, which is impossible. Hence T must be at position 5. Then P and S must occupy positions 3 and 4, in some order, and P must not sit next to T. Therefore T at 5 means position 4 cannot be P, so P must be at 3 and S at 4. Final order from left to right: R, Q, P, S, T. Thus, the person sitting to the immediate left of S is P.

Verification / Alternative check:
Check all constraints: R is at the left corner (position 1), Q sits next to R (position 2), T is not next to Q (T at 5), and P sits next to S (positions 3 and 4) but is not next to T (since T at 5 and P at 3 are separated by S). All conditions are satisfied, confirming the seating order and hence the answer.

Why Other Options Are Wrong:
Option B: Q sits to the left of P, not to the left of S.
Option C: R is two seats away from S and not immediately to the left.
Option D: T sits to the right of S, not to the left.
Option E: None of these is incorrect because P is present in the list and is correct.

Common Pitfalls:
Some learners misinterpret left and right when everyone is facing north or forget the T not next to Q condition. Others try to guess the arrangement instead of systematically checking all possibilities. Writing out the positions and carefully applying each constraint in order is the most reliable method for such problems.

Final Answer:
The person sitting immediately to the left of S is P.