Five girls R, S, T, P and Q are sitting in a row facing north. T is sitting exactly in the middle of the row. Q is sitting to the immediate right of P and to the immediate left of T. S is not sitting at either extreme end of the row. Based on this seating arrangement, who is sitting third to the left of R?

Introduction / Context:
This question is a classic linear seating arrangement problem, where five girls are seated in a single row facing north. You are given several positional clues about who sits where, and finally you must determine which girl is sitting third to the left of R. Such problems test your ability to convert verbal statements into a clear diagram and reason accurately about relative positions.

Given Data / Assumptions:

- The five girls are R, S, T, P and Q.- All of them are sitting in a single row facing north.- T sits exactly in the middle of the row.- Q is immediately to the right of P and immediately to the left of T.- S is not at any extreme end of the row.- We must find who is third to the left of R.

Concept / Approach:
In linear seating problems, it is convenient to number the seats from left to right as positions 1 to 5. Because everyone faces north, left and right are taken from the observer's point of view looking at the row. The strategy is to first place the person for whom the position is fixed (here, T in the middle), then use the relative clues for P and Q, and finally place S and R while respecting all conditions. Once the entire row is fixed, we can count the required position relative to R.

Step-by-Step Solution:
Step 1: Since there are five girls and T is exactly in the middle, T must be at position 3.Step 2: Q is immediately to the left of T, so Q must be at position 2.Step 3: Q is also immediately to the right of P, so P must be at position 1.Step 4: Thus, positions 1, 2 and 3 are fixed as P, Q and T respectively.Step 5: S is not at an extreme end. The extreme ends are positions 1 and 5. Position 1 is already occupied by P, so the only non-extreme available position for S is position 4.Step 6: The remaining person R must therefore occupy position 5.Step 7: Now the final arrangement from left to right is P (1), Q (2), T (3), S (4), R (5).Step 8: To find who is third to the left of R, start from R at position 5 and move three places to the left: position 4 (first step), position 3 (second step), position 2 (third step). The girl at position 2 is Q.

Verification / Alternative check:
Recheck each condition with the arrangement P Q T S R. T is at the centre (position 3). Q is immediately left of T and immediately right of P. S is at position 4, which is not an extreme end. All conditions are satisfied, and the relative positions are consistent. Thus, the arrangement is unique and reliable. From this arrangement, the person third to the left of R is clearly Q, so the answer is fully confirmed.

Why Other Options Are Wrong:
P is at the extreme left and not third to the left of R. S is only one place to the left of R, not three places. T is two places to the left of R. Only Q is exactly three seats to the left of R in the established arrangement, so all other options fail the required positional condition.

Common Pitfalls:
Many candidates misread the phrase describing Q's position and incorrectly place her on the wrong side of P or T. Others confuse left and right when everyone is facing north or attempt to place S at an end position by oversight. Drawing a clear diagram with numbered positions and filling in the clues one by one is the safest way to avoid such mistakes.

Final Answer:
The girl sitting third to the left of R is Q.