Question

In each of the questions below are given four statements followed by three conclusions numbered I, II, and III. You have to take the given statements to be true even if they seem to be at variance from commonly known facts. Read all the conclusions and then decide which of the given conclusions logically follows from the given statements disregarding commonly known facts.

Statements
All windows are doors.
All buildings are doors.
All doors are boats.

Conclusions
I. All windows are boats.
II. All buildings are boats.
III. Some boats are doors.

• A. Both I and II follow
• B. Both I and III follow
• C. Both II and III follow
• D. All follow
• E. None of these

Answer 1

The correct option is D All follow

Here, we drive all the inferences and conversions of the given statements
1. All windows are doors. (A-type).
Inference Some windows are doors.
Conversion some doors are windows
2. All buildings are doors (A-type).
Inference some doors are buildings.
3. All doors are boats. (A-type)
Inference some doors are boats
Conversion Some boats are doors.
(Conclusion III)
Now, we find the mediate inference between (1) and (3)
All windows are doors (A-type)
All doors are boats (A -type)
$A+A\to A$
All windows are boats.
Hence, conclusion I is true.
In statement (2) and (3) mediate inference
All buildings are doors. (A-type)
All doors are boats (A-type)
All buildings are boats (A-type)
Hence, conclusion II is true
Therefore, statement I, II, and III follows.