Answer: Jenny
Explanation:
Tim will not be in positions 1 or 4, as 1 and 4 represent the ends of the line.
Jenny cannot be in positions 1 or 4, as she is between two people.
Paco will not be in positions 2 or 4, as he is only in an odd numbered position.
Based on this, you can conclude that Maria will be in position 4, as none of the other three can be at position 4.
Paco will be in position 1, as Tim and Jenny cannot be at position 1.
The two positions left are 2 and 3. We'll assume that 1 represents the front of the line. Since Tim has to be in front of Jenny, he will take the position with the lower number, which is 2. This leaves Jenny with 3.
In order from 1 to 4, the line is as follows:
Paco, Tim, Jenny, Maria