logical deduction logical questions

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.

11.

Statements: All fish are tortoise. No tortoise is a crocodile.

Conclusions:

No crocodile is a fish.
No fish is a crocodile.

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 & Explanation

Answer: Option E

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, II follows; I is the converse of II and thus it also holds.
View Answer Workspace Report Discuss in Forum
12.

Statements: Some dedicated souls are angels. All social workers are angels.

Conclusions:

Some dedicated souls are social workers.
Some social workers are dedicated souls.

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 & Explanation

Answer: Option D

Explanation:

The first premise is an I type proposition. So, the middle term ‘angels’ forming the predicate is not distributed. The second premise is an A type proposition. So, the middle term ‘angels’ forming the predicate is not distributed. Since the middle term is not distributed even once in the premises, no definite conclusion follows.
View Answer Workspace Report Discuss in Forum
13.

Statements: No gentleman is poor. All gentlemen are rich.

Conclusions:

No poor man is rich.
No rich man is poor.

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 & Explanation

Answer: Option D

Explanation:

The first premise is an E-type proposition, So, the middle term ‘gentleman’ forming the subject is distributed. The second premise is an A-type proposition. So, the middle term ‘gentlemen’ forming the subject is distributed. Since the middle term is distributed twice, the conclusion cannot be universal. Since one premise is negative, the conclusion must be negative. Thus, it follows that ‘Some rich men are not poor’. Thus, neither I nor II follows.
View Answer Workspace Report Discuss in Forum
14.

Statements: Some swords are sharp. All swords are rusty

Conclusions:

Some rusty things are sharp.
Some rusty things are not sharp.

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 & Explanation

Answer: Option A

Explanation:

Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, I follows. Since both the premises are affirmative, the conclusion cannot be negative. Thus, II does not follow.
View Answer Workspace Report Discuss in Forum
15.

Statements: All fishes are grey in colour. Some fishes are heavy.

Conclusions:

All heavy fishes are grey in colour.
All light fishes are not grey in colour.

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 & Explanation

Answer: Option A

Explanation:

Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, it follows that ‘Some heavy things are grey in colour’. I is a cumulative result of this conclusion and the first premise. Thus, only I holds.

Leave a Reply0

Your email address will not be published.