All windows are doors. No door is wall Conclusions: 1. No window is wall 2. No…

2023

All windows are doors. No door is wall

Conclusions:

1. No window is wall

2. No Wall is door

  1. A.

    Only 1 follows

  2. B.

    Only 2 follows

  3. C.

    Either 1 and 2 follows

  4. D.

    Both 1 and 2 follows

Attempted by 71 students.

Show answer & explanation

Correct answer: D

Given premises:

  • All windows are doors.

  • No door is wall.

Reasoning:

  1. From all windows are doors and no door is wall, every window is a door and no door is a wall; therefore no window can be a wall. This yields the conclusion No window is wall.

  2. The statement no door is wall says doors and walls are disjoint sets. Disjointness is symmetric, so it also implies no wall is door. This yields the conclusion No wall is door.

Conclusion: Both conclusions follow.

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