Logical Reasoning - Logical Deduction - Discussion

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

18. 

Statements: All myths are fictions. No fiction is novel. All novels are stories.

Conclusions:

  1. No myth is novel.
  2. Some fictions are novels.
  3. Some fictions are myths.
  4. Some myths are novels.

[A]. Only either I or II and both III and IV follow
[B]. Only either I or IV and II follow
[C]. Only either I or IV and both II and III follow
[D]. All follow
[E]. None of these

Answer: Option E

Explanation:

III is the converse of first premise and so it holds.

All myths are fictions. No fiction is novel.

Since both the premises are universal and one premise is negative, the conclusion must be universal negative and should not contain the middle term. So, it follows that 'No myth is novel'. Thus, I follows.

No fiction is novel. All novels are stories.

Since the middle term 'novels' is distributed twice in the premises, the conclusion must be particular. Since one premise is negative, the conclusion must be negative.

So, it follows that 'Some stories are not fictions'.

Hence, only I and III follow.


Arvind said: (Feb 11, 2012)  
Why it is not like that - Either I or IV (complementary) and III ?

Chandu said: (Jan 6, 2019)  
Can somebody explain it in detail?

Chandu said: (Jan 6, 2019)  
Can somebody explain it in detail?

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