Key idea: This is a Constraint Table / Logic Grid puzzle with numerical ratings. The triggers are the multiple agents, multiple parameters, integer ratings 1–5, and several overlapping constraints. We must use deductive elimination on the grid to find the maximum average for Boni and minimum average for Chan.
Given constraints:
(C1) Ratings are integers from 1 to 5.
(C2) No agent received the same rating in 4 or more parameters. (So each agent has at most 3 identical ratings.)
(C3) Everyone received a score of 1 in P2 or P5 (or both).
(C4) All agents received the same rating in at least two parameters.
(C5) Fixed entries from the table: Aman P4=3, Boni P1=4, Chan P3=5, Dong P1=2, Eman P4=1.
Part (a): Maximum average rating for Boni.
Step 1: Boni has P1 = 4 fixed. To maximise the average, maximise the sum of P2+P3+P4+P5.
Step 2: By (C3), Boni must have a 1 in P2 or P5. To maximise the total, place the 1 in exactly one of these (say P2 = 1) and make the other as large as possible.
Step 3: Try P2 = 1, P3 = 5, P4 = 5, P5 = 5. Sum = 4+1+5+5+5 = 20. Average = 4.0.
Step 4: Check (C2): ratings are {4,1,5,5,5}. The rating 5 appears 3 times (P3,P4,P5). That is at most 3, so (C2) is satisfied (not 4 or more).
Step 5: Check (C4): Boni needs the same rating in at least two parameters. Rating 5 appears in P3, P4, P5 — that is 3 parameters. Satisfied.
Step 6: Check (C3): P2 = 1. Satisfied.
Step 7: Can we do better? The maximum possible sum with one forced 1 and P1=4 is 4+1+5+5+5 = 20. We cannot exceed 5 per parameter. So 20 is the maximum sum.
Step 8: Maximum average for Boni = 20/5 = 4.0.
Part (b): Minimum average rating for Chan.
Step 1: Chan has P3 = 5 fixed. To minimise the average, minimise P1+P2+P4+P5.
Step 2: By (C3), Chan must have a 1 in P2 or P5. Set P2 = 1 (minimum possible).
Step 3: Try to set remaining parameters to 1 as well: P1 = 1, P4 = 1, P5 = 1. Ratings: {1,1,5,1,1}. Sum = 9. Average = 1.8.
Step 4: Check (C2): Rating 1 appears 4 times (P1,P2,P4,P5). This violates (C2) — no agent can have the same rating in 4 or more parameters.
Step 5: Reduce the count of 1s to at most 3. We already need P2 = 1 (from C3). Set two more to 1 and one to 2: e.g., P1 = 1, P2 = 1, P4 = 1, P5 = 2. Ratings: {1,1,5,1,2}. Count of 1s = 3. OK for (C2).
Step 6: Check (C4): Chan needs the same rating in at least two parameters. Rating 1 appears in P1, P2, P4 — that is 3 parameters. Satisfied.
Step 7: Sum = 1+1+5+1+2 = 10. Average = 2.0.
Step 8: Can we get sum = 9 while satisfying (C2)? We need four 1s and one 5, but four 1s violates (C2). What about P1=1, P2=1, P4=2, P5=1? Same issue — three 1s plus the 5 and a 2 gives sum 10. Any arrangement with at most three 1s and P3=5 gives minimum sum = 1+1+5+1+2 = 10 (three 1s, one 2, one 5).
Step 9: Minimum average for Chan = 10/5 = 2.0.
Answer: (a) 4.0 (b) 2.0