Logical Reasoning - Logical Deduction - Discussion

Discussion Forum : Logical Deduction - Section 4 (Q.No. 20)
Directions to Solve

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.


20.

Statements: No man is sky. No sky is road. Some men are roads.

Conclusions:

  1. No road is man.
  2. No road is sky.
  3. Some skies are men.
  4. All roads are men.

None follows
Only I follows
Only II and III follow
Only I and III follow
None of these
Answer: Option
Explanation:

II is the converse of the second premise and so it holds.

No man is sky. No sky is road.

Since both the premises are negative, no definite conclusion follows.

No man is sky. Some men are roads.

Since one premise is particular and the other negative, the conclusion must be particular negative and should not contain the middle term. So, it follows that 'Some roads are not skies'.

No sky is road. Some men are roads.

As discussed above, it follows that 'Some men are not skies'.

Hence, only II follows.

Discussion:
3 comments Page 1 of 1.

CRAZYPHILOSPHY said:   6 years ago
As conclusion 1 and 4 are negative to each other, so the Answer should be ; II AND EITHER I OR IV.

So, the correct answer is NONE OF THESE.

Md. Zohaib said:   9 years ago
What's difference between 'none follows' and 'none of these'?

Kanagavalli priya said:   1 decade ago
I could not understand the explanation. Please someone out there explain me again. And what if the answer is given as none follows?

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