Logical Reasoning - Logical Deduction - Discussion

Discussion Forum : Logical Deduction - Section 4 (Q.No. 17)
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.


17.

Statements: All rods are bricks. Some bricks are ropes. All ropes are doors.

Conclusions:

  1. Some rods are doors.
  2. Some doors are bricks.
  3. Some rods are not doors.
  4. All doors are ropes.

Only I and II follow
Only I, II and III follow
Only either I or III, and II follow
Only either I or III, and IV follow
None of these
Answer: Option
Explanation:

All rods are bricks. Some bricks are ropes.

Since the middle term 'bricks' is not distributed even once in the premises, no definite conclusion follows.

Some bricks are ropes. All ropes are doors.

Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, it follows that 'Some bricks are doors'. II is the converse of this conclusion and so it holds.

All rods are bricks. Some bricks are doors.

Since the middle term 'bricks' is not distributed even once in the premises, no definite conclusion follows.

However, I and III involve the extreme terms. But, since they are not contradictory, they do not form a complementary pair.

Hence, only II follows.

Discussion:
10 comments Page 1 of 1.

Sonika said:   2 years ago
I think C is the answer.
(2)

Kiran Bedre said:   2 years ago
The right answer is clearly option C. Some and Some not is a complimentary pair and talk about the same elements.
Venn diagram clearly suggests that also verified from other sources clearly.
So, it's C either 1 or 3 and 2 follows!
(3)

Divya Asudani teacher from times institute delhi said:   4 years ago
Answer C is correct.

I type sensex and o type sensex making complimentary pair so they will be in either choice and second follows defineately.
(1)

Prince said:   6 years ago
It's is not C because if the conclusion is some not and all the parameters in a single Venn diagram then answer is false.
(1)

Akash said:   7 years ago
Why? if c is false then A will be the true.

Madan said:   7 years ago
No, C is not correct, because all parameters are placed in single Venn diagram then some rods are not doors becomes false, so only 2 follows.

Kuku said:   9 years ago
As per my logic, the answer is option C.
(1)

Sam said:   9 years ago
Please give Venn diagram for this question.

Tracy said:   1 decade ago
It is option C. Using the venn diagram method.

Praween said:   1 decade ago
Why not option c?

Please answer me friends if you will make venn diagram.

It is clearly option c.

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