Reasoning Study Notes: Syllogism

Dear Readers,

Today we’ll discuss about Syllogism. This topic is can fetch you marks easily but you need to know the right concepts and types of questions to practice. 

In banking exams Syllogism questions can be asked in itself. Usually 5-6 questions can be asked from this topic, thus it can fetch you easy marks with right practice.

Introduction:- The word ‘Syllogism’ is also referred to ‘Logic’. Syllogism is an important section of logical reasoning and hence, a working knowledge of its rules is required to solve the problems. In banking and IBPS exams they ask 5 questions on this hence it is an important topic for banking exams.

These questions are usually of the following nature:
Two or more statements are given and one is supposed to find out all the possible conclusions from the given statements.

Syllogism is an important topic of logical reasoning.  Generally a set of 5-6 questions asked in the competitive examination this type of question can be solved using VENN-diagram.

Note:- 1. Consider statements are always truth that is statement are universal truth. This is main                         concept of syllogism.
        2. You must understand their statement and after that, considered on their conclusion.

Statement Type

Type 1
All Books are pen
Type 2
No Book is pen
Type 3
Some Book are pen
Type 4
Some Book are not pen
Conclusion Type

Type 1
All Books are pen
Type 2
No Books are pen
Type 3
Some Books are pen
Type 4
Some Books are not pen
Type 5
All Books are pen is a
Type 6
All Books are not pen is a
Type 7
At least some books are pen
Three parts of syllogism:- (I) Positive (100%)
 (II) Negative (0%)
(III) Possibly [(50-50%) (May be or not)]
Positive parts (100%)
Example:- All and some 
Statement:- All Books are pen
                All pens are copy 
All book are copy –  √
All pen are copy – √
Some book are pen –  √
Some pen are book – √
Some copy are pen – √
Some Book are copy – √
All pen are book – X
All copy are pen – X
All copy are book – X
II. Negative parts (0%)
Example :-  No Book is pen 
Statement : –  All books are pen 
                        No pen is copy 
Conclusion:- No book is copy
        No copy is pen 
Note:-  If I relate book and copy then my statement does not fallows and always consider or work on universal truth of syllogism 
III. Possibly parts (50-50%)

Example:- Some Mango are apple is a possibilities  
Statement:- All apple are mango 
Some mango are orange 
Conclusion:- It is possible that all mango are apple – √
It is possible that some orange are not apple – √
It is possible that all apple are mango –  X
It is possible that some orange are apple –  √
Note:-  If direct relation are not given then anything can be possible, but at the any cost my statement will not wrong. 
 (a) No boy are student
 (b) Some boy are students 
Note:- Some not statement (Opposite to all)
Statement:- Some apple are orange
No orange are mango
Conclusion:-  Some apple are not mango – X
Some mango is not orange – √
Some mango is not apple – √
Note:-  We cannot prove that all apple are mango. Because in the statement it is clearly mention that there is no relation between orange and mango. 
The theory above may be summarised as:
SL. No. If the type of the given proposition is