One app for all your study abroad needs
Logical deduction questions are an important part of the Logical Reasoning section. Are you aware of the importance of being good at logical deduction? It’s a skill that comes in handy when you need to think critically and solve problems in daily life, such as when you have to make decisions or solve tricky puzzles. Logical deduction involves looking at the facts, finding patterns, and using them to draw logical conclusions.
Logical Deduction Problems are asked in exams, like
- UPSC CSE
- Defence Exams like ( AFCAT, NDA, CDS )
- State PSC Exams
- Bank (PO & Clerk) Exams
- SSC (CGL, 10+2, Steno, FCI, CPO, Multitasking)
- LIC (AAO & ADO)
- RRB
So, what are you waiting for? Start your preparation by solving these questions. In this blog, we will go over the fundamentals of logical deduction problems, as well as the types of questions asked in previous year exams and how to approach them. This will help you clear your basics and answer these logical deduction questions.
Must Read: Upcoming Government Exams
What is Logical Deduction? What are Logical Deduction Problems?
Table of Contents
Logical deduction is the process of coming to a conclusion based on one or more statements, which are also called premises. There are two Inferential Processes of Deduction:
Immediate Deductive Inference: In this case, the conclusion is inferred using any one of the three methods: conversion, obversion, or contraposition, from one of the given propositions.
1. Conversion: When you’re converting a statement, you flip the subject and predicate terms around. This means that the predicate term from the premise becomes the subject of the conclusion, and the subject from the premise becomes the predicate term. The result is known as the converse of the original proposition, which is the conclusion that you make from it.
2. Obversion: To modify a proposition’s quality, we can use a technique called obversion. Obversion involves replacing the predicate term with its complement.
3. Contraposition: To create the contrapositive of a statement, we can switch the subject and predicate terms and replace them with their complements.
Mediate Deductive Inference (SYLLOGISM): A syllogism, first presented by Aristotle, is a type of deductive argument in which a conclusion must be reached based on two statements, or premises.
Syllogism is concerned with three terms :
1. Major Term: Denoted by P (the initial letter of the word “Predicate”), it is the predicate of the conclusion.
2. Minor Term: Denoted by S (the initial letter of “Subject”), it is the topic of the conclusion.
3. Middle Term: The term represented by M (the initial letter of “Middle”) is shared by both premises.
Also Read: 20+ Questions of Puzzles in Reasoning | Logical Reasoning
20 + Logical DeductionQuestions and Answers
Below are two statements, followed by two conclusions. Assume both statements are true, even if they contradict common knowledge. Read the conclusions and choose which one logically follows from the two statements, ignoring common knowledge.
Question 1
Statements: All students who study regularly pass exams. John studies regularly.
Conclusions:
John is a student.
John will pass the exams.
A. Only conclusion I follow
B. Only conclusion II follows
C. Either I or II follows
D. Neither I nor II follows
E. Both I and II follow
Answer: Both I and II follow
Explanation: The first conclusion logically follows from the given premises because if all students who study regularly pass exams, and John studies regularly, then John must be a student. The second conclusion also follows logically because, according to the premises, if John is a student who studies regularly, he will pass exams.
Question 2
Statement: All windows are doors. No door is a wall
Conclusions:
1. No window is a wall
2. No Wall is a door
A) Only 1 follows
B) Only 2 follows
C) Either 1 or 2 follows
D) Both 1 and 2 follow
Answer: D) Both 1 and 2 follow
Explanation: Since both the premises are universal and one premise is negative, the conclusion must be universally negative. Also, the conclusion should not contain the middle term. So, 1 follows. However, 2 is the converse of the second premise, and thus it also holds.
Question 3
Statement: All dogs are mammals. Some mammals are cats.
Conclusions:
All dogs are cats.
Some cats are dogs.
A. Only conclusion I follow
B. Only conclusion II follows
C. Either I or II follows
D. Neither I nor II follows
E. Both I and II follow
Answer: Neither I nor II follows
Explanation: In this case, the premises establish that dogs are mammals, but they do not establish a direct relationship between dogs and cats. Therefore, neither of the conclusions can be logically deduced from the given premises.
Question 4
Statements: No women teacher can play. Some women teachers are athletes.
Conclusions:
Male athletes can play.
Some athletes can play.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option D
Explanation: Since one premise is negative, the conclusion must be negative. So, neither conclusion follows.
Question 5
Statements: All bags are cakes. All lamps are cakes.
Conclusions:
Some lamps are bags.
No lamp is a bag
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option C
Explanation: Since the middle term ‘cakes’ is not distributed even once in the premises, no definite conclusion follows. However, I and II involve only the extreme terms and form a complementary pair. So, either I or II follows.
Question 6
Statements: No bat is a ball. No ball is a wicket.
Conclusions:
No bat is a wicket.
All wickets are bats.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option D
Explanation: Since both the premises are negative, no definite conclusion follows.
Question 7
Statements: All flowers are trees. No fruit is a tree.
Conclusions:
No fruit is a flower.
Some trees are flowers.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option E
Explanation: The conclusion must be universally negative and should not contain the middle term. So, it follows that ‘No flower is fruit’. I is the converse of this conclusion and thus it follows. II is the converse of the first premise and so it also holds.
Question 8
Statements: All roads are poles. No pole is a house.
Conclusions:
Some roads are houses.
Some houses are poles.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option D
Explanation: Since both the premises are universal and one premise is negative, the conclusion must be universal negative. So, neither I nor II follows.
Question 9
Statements: Every minister is a student. Every student is inexperienced.
Conclusions:
Every minister is inexperienced.
Some inexperienced are students.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option E
Explanation: ‘Every’ is equivalent to ‘All’. Thus, since both the premises are universal and affirmative, the conclusion must be universal and affirmative and should not contain the middle term. So, I follow. II is the converse of the second premise and thus it also holds.
Question 10
Statement: All fishes are grey in colour. Some fishes are heavy.
Conclusions:
All heavy fishes are grey in colour.
All light fishes are not grey in colour.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option A
Explanation: Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, it follows that ‘Some heavy things are grey in colour’. I is a cumulative result of this conclusion and the first premise. Thus, only I hold.
Question 11
Statement: All fish are tortoises. No tortoise is a crocodile.
Conclusions:
No crocodile is a fish.
No fish is a crocodile.
- The only conclusion I follow
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option E
Explanation: Since both the premises are universal and one premise is negative, the conclusion must be universal negative. Also, the conclusion should not contain the middle term. So, II follows; I is the converse of II and thus it also holds.
Question 12
Statement: Some swords are sharp. All swords are rusty
Conclusions:
Some rusty things are sharp.
Some rusty things are not sharp.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option A
Explanation: Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, I follow. Since both premises are affirmative, the conclusion cannot be negative. Thus, II does not follow.
Question 13
Statement: Some papers are pens. Some pencils are pens.
Conclusions:
Some pens are pencils.
Some pens are paper.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option E
Explanation: Since both premises are particular, no definite conclusion follows. However, I is the converse of the second premise, while II is the converse of the first premise. So, both of them hold.
Question 14
Statement: Many scooters are trucks. All trucks are trains.
Conclusions:
Some scooters are trains.
No truck is a scooter.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option A
Explanation: Since the first premise is particular, the conclusion must be particular and should not contain the middle term. Thus, only I follow.
Question 15
Statements: All pens are chalk. All chairs are chalk.
Conclusions:
Some pens are chairs.
Some chalks are pens.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option B
Explanation: Since the middle term ‘chalks’ is not distributed even once in the premises, no definite conclusion follows. However, II is the converse of the first premise and so it holds.
Question 16
Statements: All men are married. Some men are educated.
Conclusions:
Some married are educated.
Some educated are married.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option E
Explanation: Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, I follow. II is the converse of I and thus it also holds.
Question 17
Statements: Some books are tables. Some tables are mirrors.
Conclusions:
Some mirrors are books.
No book is a mirror.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option C
Explanation: Since both the premises are particular no definite conclusion follows. However, I and II involve only the extreme terms and form a complementary pair. Thus, either I or II follows.
Question 18
Statements: All men are dogs. All dogs are cats.
Conclusions:
All men are cats.
All cats are men.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option A
Explanation: Since both the premises are universal and affirmative, the conclusion must be universal affirmative. However, conclusion II, being an A-type proposition, distributes the term ‘cats’. Since the term ‘cats’ is distributed in II without being distributed in any of the premises, so conclusion II cannot follow. Thus, only I follow.
Question 19
Statements: Some pastries are toffees. All the toffees are chocolates.
Conclusions:
Some chocolates are toffees.
Some toffees are not pastries.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option A
Explanation: Since one premise is particular, the conclusion must be particular and should not contain the middle term. Thus, it follows that ‘Some pastries are chocolates’, I is the converse of the second premise and so it holds. Since both premises are affirmative, the conclusion cannot be negative. Thus, II does not follow.
Question 20
Statements: All artists are smokers. Some smokers are drunkards.
Conclusions:
All smokers are artists.
Some drunkards are not smokers.
- Only conclusion I follows
- Only conclusion II follows
- Either I or II follows
- Neither I nor II follows
- Both I and II follow
Answer: Option D
Explanation: Since the middle term ‘smokers’ is not distributed even once on the premises, no definite conclusion follows.
Tips to Solve Logical Deduction Questions
Logical deduction questions require critical thinking and problem-solving skills. Here are some helpful tips and strategies to solve them effectively, explained in a simple and easy-to-understand manner:
- Read the Question Carefully: Understand all the given information.
- List the Information: Write down key points or clues.
- Draw Diagrams or Tables: Use simple sketches to visualize the problem.
- Identify Direct Clues First: Start with the obvious, straightforward information.
- Use Process of Elimination: Cross out options that don’t fit the clues.
- Look for Patterns: Spot any sequences or logical relationships.
- Apply “If-Then” Logic: Use logical reasoning to make deductions.
- Check Your Answer: Verify if your solution matches all given clues.
- Practice Regularly: The more you solve, the better you get!
Related Blogs
This was all about the “Logical Deduction”. For more such informative blogs, check out our Study Material Section, or you can learn more about us by visiting our Indian exams page.