Seven friends O, P, Q, R, S, T and U are watching a cricket match sitting in a stadium. P is sitting at one extreme end. T is sitting between Q and U. R is sitting to the immediate right of S and immediate left of Q. U is sitting second to the left of P. Who is sitting between U and P?

Let us arrange the 7 friends in a row from left to right (positions 1 to 7):
P is at one extreme end and U is sitting second to the left of P. This means P cannot be at the left end because there must be positions to its left. Thus, P must be at the rightmost extreme end:

Position 7=P
Since U is second to the left of P, U must be at position 5:

Position 5=U
T is sitting between Q and U: Since U is at position 5, T could be at position 4 or 6. If T is at position 6, then Q must be at position 7 (which is occupied by P). Therefore, T must be at position 4, and Q must be at position 3:

Position 4=T,Position 3=Q
R is sitting to the immediate right of S and immediate left of Q: Since Q is at position 3, the immediate left of Q is position 2. So, R is at position 2. R is to the immediate right of S, which means S must be at position 1:

Position 2=R,Position 1=S
Now, the only remaining position is position 6, and the remaining person is O:

Position 6=O
The complete linear arrangement from left to right is:

S, R, Q, T, U, O, P
The person sitting between U (position 5) and P (position 7) is O (position 6).