A question is given followed by two statements numbered (I) and (II). You have to decide whether the data provided in the statements are sufficient to answer the question. Read both the statements carefully and decide the appropriate answer.

5 people - P, Q, X, Y and Z, have an exam on different days of the same week between Monday and Friday.

Who has an exam on Thursday?

I. Q has an exam on Tuesday. No one has an exam between P and Q. Z has an exam immediately after X.
II. X has an exam on one of the days after Q. Only three people have an exam between P and Y2099

To determine who has an exam on Thursday, we need to analyze the information given in the main question along with the two statements individually and then together.

From the main body of the question, we have five people (P, Q, X, Y, and Z) who have exams on five different days of the same week, from Monday to Friday. The days of the week in order are: Monday, Tuesday, Wednesday, Thursday, and Friday.

Let's evaluate Statement I alone:
1. Q has an exam on Tuesday.
2. No one has an exam between P and Q, which means P's exam is either immediately before or immediately after Q. Thus, P has an exam on either Monday or Wednesday.
3. Z has an exam immediately after X. This means X and Z must occupy consecutive days (with X before Z).
Let us consider the two cases for P:
Case 1: P is on Monday. The schedule so far is: Monday (P), Tuesday (Q). The remaining days are Wednesday, Thursday, and Friday. Since Z is immediately after X, the consecutive block (X, Z) can be placed as Wednesday (X) and Thursday (Z). The remaining person, Y, would have an exam on Friday. This gives a valid schedule where Z is on Thursday.
Case 2: P is on Wednesday. The schedule so far is: Tuesday (Q), Wednesday (P). The remaining days are Monday, Thursday, and Friday. The block (X, Z) must occupy consecutive days. The only available consecutive days are Thursday and Friday. Thus, X is on Thursday and Z is on Friday. The remaining person, Y, would have an exam on Monday. This gives another valid schedule where X is on Thursday.
Since we have two different possibilities for who has an exam on Thursday (either Z or X), Statement I alone is not sufficient.

Let's evaluate Statement II alone:
1. X has an exam on one of the days after Q.
2. Only three people have an exam between P and Y. Since there are only five days in total, the only way to have exactly three people between P and Y is if P and Y are scheduled on Monday and Friday (in some order).
This statement does not give the exact position of Q, nor does it define the positions of X and Z. Thus, Statement II alone is not sufficient.

Now, let's combine Statement I and Statement II:
From Statement I, we know Q is on Tuesday, and P is either on Monday or Wednesday.
From Statement II, we know P and Y must be on Monday and Friday (in some order).
Since P must be on Monday or Friday to satisfy Statement II, and P must be on Monday or Wednesday to satisfy Statement I, P must be on Monday. Consequently, Y must be on Friday.
Now we can construct the unique schedule:
- Monday: P
- Tuesday: Q (given in Statement I)
- Wednesday: The remaining days are Wednesday and Thursday. We know from Statement I that Z has an exam immediately after X. Thus, X and Z must be on consecutive days. The only remaining consecutive slot is Wednesday and Thursday.
Therefore, X has an exam on Wednesday, and Z has an exam on Thursday.
Let us verify the conditions:
- Schedule: Monday (P), Tuesday (Q), Wednesday (X), Thursday (Z), Friday (Y).
- Q is on Tuesday (Satisfied).
- No one is between P and Q (P is Monday, Q is Tuesday - Satisfied).
- Z is immediately after X (X is Wednesday, Z is Thursday - Satisfied).
- X is after Q (Wednesday is after Tuesday - Satisfied).
- Three people between P and Y (P is Monday, Y is Friday, with Q, X, Z in between - Satisfied).
This combined data uniquely determines that Z has the exam on Thursday.

Thus, the data in statements I and II together (and not statement I alone or statement II alone) is sufficient to answer the question.