Five friends — P, Q, R, S, T — sit in a row facing south.. R is to the immediate right of Q. T is at an end but not next to R. S is between P and Q. P is not at any end.

Given facts (facing south — note the directional effect):

• R is to the immediate right of Q. (When people face south, “right” for them corresponds to the viewer’s left on the page, so R will be immediately to the left of Q in our left→right diagram.)

• T is at an end but not next to R.

• S is between P and Q (i.e., P and Q are on the two sides of S).

• P is not at any end.

Reasoning (use positions 1→5 left→right):

1. From “R is immediately right of Q” and the facing-south mapping, in the diagram R must be immediately to the left of Q: ..., R, Q, ....

2. S is between P and Q means the three appear consecutively as either P - S - Q or Q - S - P (left→right).

3. If P - S - Q held, Q’s left neighbor would be S, but we require R to be immediately left of Q; that would force R = S (impossible). So the only feasible ordering for these three is R, Q, S, P consecutively (because R must be left neighbor of Q, and S must be the other neighbor of Q). That gives the block R Q S P.

4. This block takes four consecutive seats; the leftover seat is the remaining end, which must be occupied by T. Also P must not be at an end, so the block must occupy positions 1–4 (so P is at pos4, not an end). Therefore T must be at position 5. T is at an end and is not adjacent to R (R is at pos1) — that satisfies the “not next to R” condition.

Unique valid arrangement (left → right):
R — Q — S — P — T