Syllogism Logical Reasoning Questions and Answers Part 5

17. Considering given statements as true, select a logical conclusion based on the given statements.

Statements:
All A are B
Some B are C

Conclusions:
(I) Some C are A.
(II) All A being C is a possibility.

a. Only conclusion I follows
b. Only conclusion II follows
c. Either conclusion I or II follows
d. Neither conclusion I nor II follows

Answer: b. Only conclusion II follows

Explanation:

For a conclusion to be true, it has to be true in every possible Venn diagram.
In a conclusion having the word 'possibility', like conclusion (II), for the conclusion to be true, we must have at least one Venn diagram that shows that the conclusion is true and at least one that shows that the conclusion is false.

syllogisms


18. Considering given statements as true, select a logical conclusion based on the given statements.

Statements:
Some doors are window.
No window is a house

Conclusions:
(I) All house being door is a possibility.
(II) At least some house is a window.

a. Only conclusion I follows
b. Only conclusion II follows
c. Either conclusion I or II follows
d. Neither conclusion I nor II follows

Answer: a. Only conclusion I follows

Explanation:

For a conclusion to be true, it has to be true in every possible Venn diagram.
In a conclusion having the word 'possibility', like conclusion (II), for the conclusion to be true, we must have at least one Venn diagram that shows that the conclusion is true and at least one that shows that the conclusion is false.
       
syllogisms


19. Considering given statements as true, select a logical conclusion based on the given statements.

Statements:
All elephants are rat.
No rat is a dog
All dogs are lions

Conclusions:
(I) No lion is elephant.
(II) All rats being lions is a possibility.
(III) All elephants being lions is a possibility

a. Only conclusion I and III follows
b. Only conclusion II follows
c. Only conclusion II and III follows
d. Neither conclusion I nor II follows
e. All follow

Answer: c. Only conclusion II and III follows

Explanation:

For a conclusion to be true, it has to be true in every possible Venn diagram.
In a conclusion having the word 'possibility', like conclusion (II), for the conclusion to be true, we must have at least one Venn diagram that shows that the conclusion is true and at least one that shows that the conclusion is false.
       
syllogisms


20. Considering given statements as true, select a logical conclusion based on the given statements.

Statements:
No stone is metal.
Some metals are papers.
All papers are glass.

Conclusions:
(I) Some metals being glass is a possibility.
(II) At least some glasses are metals.
(III) No stone is paper

a. Only conclusion I and II follows
b. Only conclusion II follows
c. Only conclusion II and III follows
d. Only I follows
e. All follow

Answer: b. Only conclusion II follows

Explanation:

For a conclusion to be true, it has to be true in every possible Venn diagram.
In a conclusion having the word 'possibility', like conclusion (II), for the conclusion to be true, we must have at least one Venn diagram that shows that the conclusion is true and at least one that shows that the conclusion is false.

syllogisms

In all possible Venn diagrams, some or all metals are glasses. So, conclusion I is invalid.

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