21. Ten students, P, Q, R, S, T, U, V, W, X, and Y, are participating in a quiz contest held on different days in two weeks (Monday to Friday). Each student participates on one unique day, and no quiz is held on weekends. The conditions are as follows:
1. P participates earlier than R.
2. V is on Monday of the second week.
3. S is scheduled two days after T.
4. U and W have consecutive day slots.
5. Y's quiz is not on a Friday.
6. Q is scheduled before both P and Y.
7. X is scheduled on Thursday of the first week.
Given X on Thursday in the first week, V on second Monday, and S two days after T, arranging U and W consecutively leads to: Week 1: Q-Monday, R-Tuesday, P-Wednesday, X-Thursday, T-Friday; Week 2: V-Monday, U-Tuesday, W-Wednesday, S-Thursday, Y-Friday.