There are 4 people S, D, K and L sitting in a row facing North. If D and K are sitting at the left end and right end respectively, and S is sitting second from the left end, then how many people are sitting to the right of S?

There are 4 positions in the row from left to right: 1, 2, 3, 4.
* D is sitting at the left end $\to$ Position 1 = D
* K is sitting at the right end $\to$ Position 4 = K
* S is sitting second from the left end $\to$ Position 2 = S

The remaining person L will occupy the remaining vacancy $\to$ Position 3 = L.
So the full arrangement from left to right is: D, S, L, K.

The people sitting to the right of S are L and K.
Therefore, there are $2$ people sitting to the right of S.