Logical Deductions(Syllogisms):

A Venn diagram is a one type of diagram where circles may overlap showing the differences between two or more things. Based on the given data you need to draw the circles whether it should overlap or not.

What is Syllogism?

Syllogism is defined as inference or logical deduction drawn from the given statements.For Ex.

Man is a king

Ravi is a man

Therefore Ravi is a king.

From given two statements we derived a logical conclusion “Ravi is a king”

The following basic concepts and terminologies in this topic must be understood before we go ahead.

A. Preposition: It is also called as Premise. It is a complete sentence having subject, predicate and copula.

Ex:          Man is great

                Man – Subject

                Is - Copula          

                Great – Predicate

B. Types of Prepositions: Prepositions have been classified based on preposition is,

a)      Negative

b)      Affirmative

c)       Universal

d)      Particular

 

Symbol                 Preposition                           Quantity                              Quality                  Example

 A                           All S or P                          Universal                             Affirmative            All boys are gems

 E                           No S is P                           Universal                             Negative              No man is good

 I                            Some S are P                    Particular                             Affirmative          Some girls are gems

 O                           Some S are Not P              Particular                             Negative             Some pens are not bad

 

Previous year solved questions:

1. Statements:                          All cups are bottles

                                                Some bottles are jugs

                                                No jug is plate

                                                Some plates are tables

Conclusions:                              I. Some tables are bottles

                                                II. Some plates are cups

                                                III. No table is bottle

                                                IV. Some jugs are cups

A) Only I follows                                                                               B) Only II follows

C) Only III follows                                                                             D) Only IV follows

E) Only either I or III follows

Ans: E

Solution: Some bottles are jugs + No jug is plate = I + E = O

Some bottles are not plates + Some plates are tables = O + I =No conclusion

Hence, I and III do not follow by combination. However, either I or III follows because they form a complementary I – E pair. All cups are bottles + some bottles are jugs = A + I = No conclusion.

Hence IV does not follow. Neither does II follow.

 

2. Statements:                          Some chairs are handles

                                                All handles are pots

                                                All pots are mats

                                                Some mats are handles

Conclusions:                              I. Some buses are handles

                                                II. Some mats are chairs

                                                III. No bus is a handle

                                                IV. Some mats are handles

A) Only I, II and IV follow                                                              B) Only II, III and IV follow

C) Only either I or III and II follow                                             D) Onlyeither I or III and IV follow

E) Only either I or III, II and IV follow

Ans: E

Solution: All handles are pots + All pots are mats = A + A = A = All handles are mats -> conversion -> some mats are handles (I). Hence IV follows.

All handles are mats + Some mats are buses = A + I = No conclusion.

However I and III form a complementary pair.Hence either I or III follows.

Some chairs are handles + All handles are mats = I + A = I = Some chairs are mats -> Conversion ->

Some mats are chairs (I). Hence II follows.