Difficulty: Medium
Correct Answer: Between B and C
Explanation:
Introduction / Context:Multiple adjacency and end constraints determine a unique line-up for five seats, allowing us to pinpoint A’s exact position relative to neighbors.
Given Data / Assumptions:
Concept / Approach:Since C is at seat 4, A must be adjacent to C at seat 3 or 5. Because A must also be next to B and to the right of B and E, A fits at seat 3 with B at seat 2. Then C at seat 4 is next to D at seat 5, and D is not adjacent to E at seat 1.
Step-by-Step Solution:
Place E at seat 1; C at seat 4.To satisfy “A with C” and “A next to B” with A to the right of B: put A at seat 3 and B at seat 2.C (seat 4) must be next to D ⇒ D at seat 5. All constraints hold.Verification / Alternative check:Trying A at seat 5 fails because then A cannot be to the right of B and simultaneously adjacent to C with C fixed at seat 4.
Why Other Options Are Wrong:The only neighbors of A in the valid layout are B (left) and C (right).
Common Pitfalls:Forgetting C’s fixed position (second from right) forces A to be at seat 3, not at an edge.
Final Answer:Between B and C
Discussion & Comments