Tricks to Solve Syllogism Questions using Venn Diagram for CAT and other MBA Exams



A syllogism is a kind of logical argument in which one proposition (the conclusion) is inferred from two or more others (the premises). 
Question based on syllogism forms an important part of Logical Reasoning section of various MBA exams and even job aptitude tests. Below are the tips which would be handy in solving syllogism problems:


Tip #1
Solve the questions through a Venn Diagram. Always make sure common areas are shaded do give you a correct answer.

Example of Solving syllogism using venn diagram:
Statement 1: All women are mothers.
This could be represented using venn diagram as


Explanation
In simple words this represents that mothers is a bigger group and women belongs to this group. There might be other members of Mothers group apart from Women. Hence all mothers are women would be incorrect.

Statement 2: All mothers are caring
This could be represented using venn diagram as (Caring is represented by the entire bigger circle outlined by black line)

Explanation
This represents that Caring is a bigger group and mothers belongs to this group. Looking at the venn diagram we can say that all Caring are not mothers. Furthermore looking it at the venn diagram it’s easy to conclude that:
All Women are caring
Reasons:
As all mothers are caring and all women are mothers => This implies All Women are caring (the same could be easily inferred from venn diagram as Caring is the biggest set and women is part of it as it is part of Mothers)
 

Tip #2
Shortcut rules (if Venn Diagrams are confusing you) between Statement 1 and Statement 2 in that order
All + All = All
All + No = No
All + Some = No Conclusion
Some + All = Some
Some + Some = No Conclusion
Some + No = Some Not
No + No = No Conclusion
No + All = Some not reversed
No + Some = Some not reversed


Tip #3
You can cancel out common terms in two statements given, then on the remaining terms apply the syllogisms rules and solve. E.g. Some dogs are goats, All goats are cows. Cancel out "goats" which leaves us with Some dogs are...all are cows. Important words remaining are ALL and SOME in that order. SOME + ALL = SOME, hence conclusion is SOME dogs are cows.


Tip #4
Interchange between reading the question as well as the conclusion before arriving at the answers. Always evaluate each and every conclusion to find out how many conclusions are possible.



Tip #5
Avoid using common knowledge as Syllogisms questions usually state unnatural statements

 
Tip #6
Remember some implications
All <=> Some, e.g. All A are B also implies Some A are B (being a subset) and Some B are A
Some <=> Some, e.g. Some A are B also implies Some B are A
No<=> No, e.g. No A are B also implies No B are A


Also Check:

1 comment:

  1. In the first venn diagram, shouldn't mothers be the subset of women?

    Regards,
    Creately

    ReplyDelete

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