UPSC Prelims 2018·CSAT·Logical Reasoning·Arrangement and Puzzles

The plan of an office block for six officers A, B, C, D, E and F is as follows: Both B and C occupy offices to the right of the corridor (as one enters the office block) and A occupies on the left of the corridor. E and F occupy offices on opposite sides of the corridor but their offices do not face each other. The offices of C and D face each other. E does not have a corner office. F's office is further down the corridor than A's, but on the same side. If E sits in his office and faces the corridor, whose office is to his left?

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Last updated 23 May 2026, 3:31 pm IST
  1. AA
  2. BB
  3. CCCorrect
  4. DD

Explanation

Let's break down the office layout step-by-step: 1. **Officers on each side:** * B and C are on the Right side of the corridor (R). * A is on the Left side of the corridor (L). * F's office is on the same side as A (L). So, F is on the Left side. * E and F are on opposite sides. Since F is on L, E must be on R. * C and D face each other. Since C is on R, D must be on L. * Summary: Left Side (L): A, D, F. Right Side (R): B, C, E. 2. **E's position:** * E does not have a corner office. This implies there are at least three offices on E's side (R), and E occupies the middle one. Let's assume offices are numbered 1, 2, 3 along the corridor. So, E is in R2. 3. **C and D's positions:** * C and D face each other, meaning they are at the same office number across the corridor (e.g., L1 faces R1, L2 faces R2, L3 faces R3). * Since E is at R2, C cannot be at R2. So C is either R1 or R3. * F does not face E. Since E is at R2, F cannot be at L2. So F is either L1 or L3. 4. **F and A's positions:** * F's office is further down the corridor than A's, on the same side (L). This means A comes before F on the Left side. 5. **Constructing the layout (Trial 1):** * Assume C is at R1. Then D must be at L1 (as they face each other). * Current layout: L1: D | R1: C L2: ? | R2: E L3: ? | R3: ? * On the Left side, we have A and F remaining. F cannot be L2 (as F does not face E). So F must be L3. * If F is L3, then A must be L2 (since A comes before F). * On the Right side, B is the only officer remaining, so B must be at R3. * Proposed Layout: Side L | Side R Office 1: D | C Office 2: A | E Office 3: F | B 6. **Verify the layout:** * B, C on R (C at R1, B at R3) - Yes. * A on L (A at L2) - Yes. * E, F opposite sides (E at R2, F at L3) - Yes. * E, F offices do not face each other (R2 and L3 don't face) - Yes. * C, D face each other (C at R1, D at L1) - Yes. * E does not have a corner office (E at R2 is a middle office) - Yes. * F's office further down than A's, same side (F at L3 is further down than A at L2) - Yes. * This layout is consistent with all conditions. 7. **Answer the question:** * "If E sits in his office and faces the corridor, whose office is to his left?" * E is in Office R2. If E faces the corridor, he is looking across towards the Left side (L). * From E's perspective, looking out into the corridor: * His left is towards Office R1. * His right is towards Office R3. * Office R1 is occupied by C. Therefore, C's office is to E's left. The final answer is C
Logical Reasoning: The plan of an office block for six officers A, B, C, D, E and F is as follows: Both B and C occupy offices to the right

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