In each of the following questions two statements are given and these…
2023202320252023
In each of the following questions two statements are given and these statements are followed by two conclusions numbered (1) and (2). You have to take the given two statements to be true even if they seem to be at variance from commonly known facts. Read the conclusions and then decide which of the given conclusions logically follows from the two given statements, disregarding commonly known facts. Statements: All the windows are doors. No door is a wall. Conclusions: I. Some windows are walls. II. No wall is a door.
- A.
Only (1) conclusion follows
- B.
Only (2) conclusion follows
- C.
Either (1) or (2) follows
- D.
Neither (1) nor (2) follows
Attempted by 58 students.
Show answer & explanation
Correct answer: B
Answer: Only conclusion II ("No wall is a door") follows.
Reason:
From "All the windows are doors" we know every window is a door.
From "No door is a wall" we know doors and walls are disjoint; there is no element that is both a door and a wall.
Because windows are a subset of doors and doors do not overlap with walls, no window can be a wall. Therefore the first conclusion, "Some windows are walls," is false.
The second conclusion, "No wall is a door," follows directly from the premise that no door is a wall, since the lack of overlap between doors and walls is symmetric: there are no walls that are doors.