Q1. Arrangements
MCQ · +3 / −1
Which two candidates can belong to the same department?
- A) Prof. Pakrasi and Prof. Samuel
- B) Prof. Qureshi and Prof. Ramaswamy
- C) Prof. Pakrasi and Prof. Qureshi
- D) Prof. Ramaswamy and Prof. Samuel
Correct Answer
C) Prof. Pakrasi and Prof. Qureshi
Step-by-step solution
📌 Core Concept
The four candidate-to-candidate votes plus the block-voting rule fix the department sizes of the non-candidate groups. That fixes where each candidate sits.
🔢 Step-by-Step Solution
1
The candidates' own votes are S→P, P→R, R→Q and Q→S. Each candidate gets exactly 1 vote this way.
2
The non-candidates therefore cast the remaining votes: P 2, Q 13, R 5, S 0. That is 20 votes.
3
Each department's non-candidates vote as one block. O&Q has one candidate, so its block is 4. The other 3 candidates sit in F&A, M&S and B&H, with at most 2 per department.
4
P needs a block of exactly 2. Only B&H can give that, with 1 candidate (3 − 1 = 2). The other two candidates are then in F&A and M&S.
5
The blocks left are O&Q 4 and F&A and M&S , where . Only gives blocks 4, 9, 5. Then Q's 13 = 4 + 9, and R's 5 is the M&S block.
6
So F&A has no candidate and M&S has two. The M&S block votes R, so R is not in M&S. The O&Q block votes Q, so Q is not in O&Q. Q is therefore in M&S or B&H.
7
If Q were in B&H, P and S would both be in M&S. But S voted for P, which breaks rule 3. So Q is in M&S.
8
Q's partner in M&S cannot be S, because Q voted for S. It cannot be R either. So it is P, and Prof. Pakrasi and Prof. Qureshi share M&S.
Why Not the Others
A: Samuel voted for Pakrasi, so they cannot share a department.
B: Ramaswamy voted for Qureshi, so they cannot share a department.
D: Ramaswamy and Samuel occupy O&Q and B&H, one each.
Correct Answer: C