Logical Reasoning - Logical Deduction - Discussion

Discussion Forum : Logical Deduction - Section 1 (Q.No. 31)
Directions to Solve

In each question below are given two statements followed by two conclusions numbered I and II. 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 conclusion and then decide which of the given conclusions logically follows from the two given statements, disregarding commonly known facts.

Give answer:

  • (A) If only conclusion I follows
  • (B) If only conclusion II follows
  • (C) If either I or II follows
  • (D) If neither I nor II follows and
  • (E) If both I and II follow.


31.

Statements: All windows are doors. No door is wall.

Conclusions:

  1. No window is wall.
  2. No wall is door.
Only conclusion I follows
Only conclusion II follows
Either I or II follows
Neither I nor II follows
Both I and II follow
Answer: Option
Explanation:
Since both the premises are universal and one premise is negative, the conclusion must be universal negative. Also, the conclusion should not contain the middle term. So, I follows. However, II is the converse of the second premise and thus it also holds,
Discussion:
9 comments Page 1 of 1.

Vaishnavi said:   1 decade ago
How come a middle term come in a conclusion?

Srinivasan said:   1 decade ago
What is middle term?

Jay said:   1 decade ago
Middle term is the term that is common to both the premises.

Aryan said:   1 decade ago
Can you explain it how?

Sam said:   1 decade ago
Its quite contradictory the manner in which the deduction takes place here since middle term can never be part of conclusion so the answer should be (A).

Rahul said:   9 years ago
Middle term should not be a part of conclusion.

Ramya said:   8 years ago
How can middle term be part of conclusion? Someone please explain.

Manav said:   8 years ago
According to me, the answer should be A not E.

Mandal said:   4 years ago
Here the answer is E because:

1. Conclusion 1 is simple for all I guess from the laws of deduction.
2. If you reverse the second premise "No door is wall", the converse of it gives "No wall is doors" and hence conclusion 2 is valid and hence option is E.

Post your comments here:

Your comments will be displayed after verification.