Logical Reasoning - Logical Deduction - Discussion

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.

39. 

Statements: Some books are tables. Some tables are mirrors.

Conclusions:

  1. Some mirrors are books.
  2. No book is mirror.

[A]. Only conclusion I follows
[B]. Only conclusion II follows
[C]. Either I or II follows
[D]. Neither I nor II follows
[E]. Both I and II follow

Answer: Option C

Explanation:

Since both the premises are particular no definite conclusion follows. However, I and II involve only the extreme terms and form a complementary pair. Thus, either I or II follows.

Muthu said: (Mar 11, 2011)  
When should either be chosen? I think option D is correct.

Sanyam said: (Sep 25, 2011)  
Option D is correct by Venn diagram also...

Phani said: (Dec 26, 2013)  
Can you explain this properly because I got "D" according to venn diagrams so how could it be "C".

Saurabh said: (Sep 16, 2014)  
It should be D because if both the statements include some then no conclusion can be made.

Maimuna Ambareen said: (Nov 10, 2014)  
Since both premises are particular the conclusion does not follow. If I am wrong please correct me. I have written test scheduled this week.

Trishul said: (Jul 17, 2015)  
Answer should be D.

From the given premise two extremes can be drawn:

Some books are mirrors.
No book is mirror.

But in the question it is given 'some mirror are books' which is NOT a converse of 'some book are mirror'.

Add said: (Aug 15, 2015)  
Answer C is correct because depending on how you draw your venn diagram, either 1 or 2 can be correct, but not at the same time.

Jyoti said: (Oct 18, 2015)  
Can someone please explain with a venn diagram how is the answer C ?

Yash said: (Nov 27, 2015)  
The correct answer is C. The logic is simple. Some books are tables, and some tables are mirrors right. So either some mirrors can be books or no mirror can be books.

K.N.Jayanth Krishnamoorthy said: (Feb 24, 2016)  
In my opinion, D is the correct answer. Please tell me where I am going wrong. My bone of contention, is as follows:

Some books are tables. Some tables are mirrors.

Taking the 1st statement, it can be deduced that some books are tables. Therefore all tables are books.

Similarly, in the 2nd statement, it can be deduced that some tables are mirrors. Therefore, all mirrors are tables.

The choices given are: some mirrors are books; no book is mirror. Both of these conclusions cannot be drawn and hence D is the answer.

Can someone please explain why am I wrong?

P.T said: (Jul 7, 2016)  
This question is similar to the following question:

1. Some doctors are fools 2. Some fools are rich.

Ans both options contain the extreme terms for this question too, but in the solution, it's been said that there's no definite conclusion.

Whereas for the question (1. Some books are tables. ), it's been said that either 1 or 2 follows. Why?

Can someone kindly explain this?

Vikey said: (Sep 5, 2016)  
I have studied in CAT that when there are two premises in the question, no conclusion can be drawn. So how the answer is C not D?

Amb said: (Oct 7, 2016)  
The answer is D only.

To apply either or case three conditions have to be fulfilled,
1. One conclusion should be positive and one negative.
2. Both the conclusions should be individually wrong.
3. The elements in both conclusion should be same.

Like in above case through Venn diagram, First condition one is positive and 2 is negative
Second condition both are wrong, Third condition is not fulfilled as in 1 conclusion element is mirror and book but in second conclusion it is book and mirror. As a result third condition is not fulfilled. So, we cannot apply option C.

So, the answer is D only.

S.N. said: (Jun 1, 2017)  
C is wrong because the statement 'no book is a mirror' contradicts both initial statements, when we're instructed to take both statements as true. C is also wrong because 'some mirrors are books' also contradicts the initial statements, because if we assume that some books are tables and some tables are mirrors, mirrors cannot be anything else other than a book (a table, at least one of which is a mirror, is also a book).

The only way C can be correct is if a mirror could be anything other than a book, but that would've required further information in the question (which was not given). The instructions and setup we are given means we think of all our choices not as a Venn diagram, but as a box (or a circle, triangle, whatever other shape you like). Now think of some of those books as tables (a smaller box encased within the outer box). Then think of some of those tables as mirrors (an even smaller box inside the inner box). You can't possibly have a mirror that's not also a book in this layout, given this setup. Again, that would have required different information and instructions.

So, given this, only D can be correct.

Yogendra Ray said: (Sep 4, 2017)  
Book to Table and Table to Mirror implies Book to Mirror.

A is correct.

Post your comments here:

Name *:

Email   : (optional)

» Your comments will be displayed only after manual approval.