Six friends are sitting in a circle facing the centre. Adam is sitting to the immediate left of Betty. Charlie is sitting to the immediate right of Frank. Betty is sitting between Adam and Dan. Eve is sitting between Dan and Frank. Who is sitting to the immediate left of Frank?

Let the six friends be arranged in a circle facing the centre.
1. Adam is sitting to the immediate left of Betty. If we place Betty at position 1, Adam is at position 2 (going clockwise since facing inside means left is clockwise).
2. Betty is between Adam and Dan. This implies Dan is on the other side of Betty, so Dan is at position 6 (counter-clockwise from Betty).
3. Eve is between Dan and Frank. Since Dan is at position 6, Eve must be at position 5, and Frank must be at position 4.
4. Charlie is sitting to the immediate right of Frank. Frank is at position 4, so his immediate right (counter-clockwise) is position 3, which is filled by Charlie.

Checking the full circular layout in order:

$$\text{Betty}\to \text{Adam}\to \text{Charlie}\to \text{Frank}\to \text{Eve}\to \text{Dan}\to (\text{back to Betty})$$

Looking at Frank (facing centre):

* To his immediate right is Charlie.
* To his immediate left is Eve.