Question

In each of the questions below are given four statements followed by three conclusions numbered I, II & Ill. 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
Some windows are doors.
All doors are walls.
No wall is a roof.
All roofs are shelters.

Conclusions
I. Some windows are walls.
II. No wall is a shelter.
Ill. No door is a shelter.

• A. None follows
• B. Only II and III follow
• C. Only I and II follow
• D. Only I follows
• E. None of these

Answer 1

The correct option is D Only I follows

The first premise is a particular affirmative (I-type).
The second and fourth premises are universal affirmative (A-type).
The third premise is a universal negative (E-type).
Some windows are doors.
All doors are walls.
$I+A=I$-type conclusion.
Some windows are walls.
This is conclusion I.
All doors are walls.
No wall is a roof.
$A+E\Rightarrow E$-type conclusion.
No door is a roof.
All roofs are shelters.
$E+A\Rightarrow O_1$-type conclusion.
Some shelters are not doors.
No wall is a roof.
All roofs are shelters.
Some shelters are not walls.