Order and Ranking - Party Drinking and Leaving

Let's establish the departure order from earliest to latest:

1. W left earlier than V $\implies W < V$.
2. P left later than V $\implies V < P$.
3. T left later than P and earlier than S $\implies P < T < S$.
4. U left later than S $\implies S < U$.

Combining departure times: $W < V < P < T < S < U$. Therefore, W left the earliest.

Let's establish the drinking order from most to least:

1. Q drank more than U, U drank more than V $\implies Q > U > V$.
2. T drank less than V and more than P $\implies V > T > P$.
3. P drank more than W $\implies P > W$.
4. W drank more than R $\implies W > R$.

Combining drinking quantities: $Q > U > V > T > P > W > R$. Therefore, R drank the least.