A single simple trick to solve all Syllogism problems in IAS CSAT Paper II


Numerous IAS Aspirants have mastered syllogism problems (logical reasoning) through the four free youtube videos at Examrace Channel. Every single syllogism problem can be solved using the Venn Diagram technique discussed in these videos. Without learning the systematic techniques, syllogism problems could only be solved by guess work - which from our experience most students get wrong.

  1. Syllogism Part 1 talks about square of opposition, basic venn diagram technique and introduces the concept of categorical propositions. It lays the foundation for classifying various problems.
  2. Syllogism Part 2 discusses the unconditional valid forms - EIO, OAO, AEE, AOO and IAI.
  3. Syllogism Part 3 talks about conditional valid forms and existential fallacy - the cases discussed are AAI, AEO and EAO.
  4. Syllogism Part 4 explains the problems from past year papers which are solved using the techniques explained in the above three lectures.

Following 10 examples have been discussed and solved in the above video. Doubts and clarifications are most welcome as comments on Youtube Videos - Most comments are answered within 24 hours.

Example 1:

Premise: All events are things describable by science.

Premise: All mental decisions are events.

Example 2:

Conclusion: All mental decisions are things describable by science.

Premise: All businessmen are wealthy Premise: All wealthy people are hard working. Conclusion:

All businessmen are hard working?

All hard working people are not wealthy?

Example 3:

Premise: Some religious people are morally good.

Premise: Some religious people are rational.


Rationally religious people are good morally.

Non - rational religious persons are not morally good.

Example 4:

Premise: Some flowers are red.

Premise: Some flowers are blue.


Some flowers are neither red nor blue.

Some flowers are both red and blue.

Example 5:

All pens are books Some pencils are pens


1. Some pencils are books 2. All pens are pencils

Example 6:

All pens are books No pencils are books


1. All books are pencils 2. All pencils are books 3. Some pencils are books

Example 7:

Some decisions are reflections.

All dreams are decisions.

Conclusion: Some dreams are reflections.

Example 8:

All free decisions are uncaused happenings.

No conclusions are uncaused happenings.

Conclusion: No conclusions are free decisions.

Example 9:

No physical acts are chance occurrences.

All chance occurrences are accidental events.

Conclusion: No accidental events are physical acts.

Example 10:

All lorrys are bikes

All lorrys are cars


1. All bikes are cars

2. Some cars are bikes

- Published/Last Modified on: August 18, 2015

IAS Upd.

Sail through IAS Mains and Prelims: Fully-explained Prelims (Both GS & Aptitude) problems with detailed solutions. Notes & detailed answers for Mains GS, Essay, Complulsory (Hindi and English) papers and optionals.