Four friends M, N, O and P are sitting in a straight line, all facing the North direction. O is sitting at the extreme right end. P is third to the left of O. M is sitting exactly between P and N.
What is the exact seating arrangement from left to right?

Let's list the positions from 1 to 4 from left to right: $\text{\_ \_ \_ \_}$
1. O sits at the extreme right end $⟹$ Position 4 is $\text{O}$.
2. P is third to the left of O $⟹$ Position $4-3=1$ is $\text{P}$.
Current layout: $\text{P \_ \_ O}$.
3. M sits exactly between P and N. Since position 1 is P, position 4 is O, the remaining slots are 2 and 3. For M to be between P and N, position 2 must be $\text{M}$ and position 3 must be $\text{N}$.
Final arrangement from left to right: $\text{P-M-N-O}$.