Based on the statements, the linear arrangement is
1 2 3 4 5 6
↓ ↓ ↓ ↓ ↓ ↓
- - P - - T
T dances sixth only if P dances third.
Which means that T can only be in the sixth position if P is in the third position.
The arrangement implies:
1. - 2. - 3. P 4. - 5. - 6. T
Therefore, T dancing in the sixth position is contingent upon P dancing in the third position.
The positions represented as (-) can be filled with other dancers, but the specified positions for P and T are as described.