In a race, five participants, P1, P2, P3, P4, and P5, finished in the following order: P1 finished before P3 but after P2. P4 finished before P5 but after P3. What is the correct sequence of finishers?
A class consists of six students: P, Q, R, S, T, and U. The selection criteria are: 1) P cannot be selected if Q is selected. 2) R must be selected if S is selected. 3) T can be selected only if U is not selected. Which of the following combinations is valid?