CLAT Logical Reasoning
Critical reasoning, type by type
Spot it, solve it, dodge the trap
Most of CLAT’s 22–26 Logical Reasoning questions are one of 8 kinds. Each asks something different of the same short argument. Learn to tell them apart from the question stem, and each has a method.
Updated
The method for every type
Read the question stem first, so you know what the passage is for.
Find the conclusion: the claim the rest of the passage is there to support.
Name the gap between the evidence and the conclusion, in your own words.
Predict the answer before you read the options, then eliminate.
Jump to: Main conclusion · Assumption · Strengthen · Weaken · Inference · Flaw · Course of action · If-then statements
1Main conclusion
“Which of the following best expresses the main point of the passage?”
- Method
- Ask what the author wants you to believe. The conclusion is supported by the other sentences and supports none of them. Signal words help (so, therefore, clearly, should) but the conclusion can come first.
- Trap
- A premise restated in new words, or a statement that is true but narrower or wider than what the author argues.
Night classes at the district library drew 300 adults last year, more than the two colleges in town managed together. The council plans to cut the library’s evening hours to save electricity. Since most of those adults work during the day, the cut would take away the only time they can study. The council should look for its savings elsewhere.
Which of the following best expresses the main conclusion?
- A The library’s night classes are more popular than the colleges’ classes.
- B The council should find savings other than cutting the library’s evening hours.
- C Most adults at the night classes work during the day.
- D The council wants to save electricity.
Answer: B. Every other sentence is a reason for the last one. A and C are premises; D is the council’s aim, which the author argues against meeting this way.
Practise: Statement and Conclusion
2Assumption
“The argument assumes which of the following?” or “depends on”
- Method
- An assumption is a premise the author needs but never states. Test an option by negating it: if the negation breaks the argument, it is an assumption.
- Trap
- An option that would help the argument but is not needed, often worded in absolutes (always, all, only).
Ravi scored higher in his second mock than in his first. So the revision he did between the two mocks improved his score.
The argument assumes that:
- A Ravi revised for at least ten hours between the mocks.
- B The second mock was not markedly easier than the first.
- C Revision always improves mock scores.
- D Ravi will score higher still in a third mock.
Answer: B. Negate B: if the second paper was much easier, the rise proves nothing about revision, and the argument falls. C would help, but the argument does not need “always”.
Practise: Statement and Assumption
3Strengthen
“Which of the following, if true, most strengthens the argument?”
- Method
- Find what else could explain the evidence, then pick the option that rules it out or closes the gap. Treat every option as true.
- Trap
- An option on the right topic that leaves the link between evidence and conclusion untouched.
After the town put up new streetlights, thefts at night fell by a third. The new lights caused the fall.
Which of the following, if true, most strengthens the argument?
- A The lights cost less than the council expected.
- B Night thefts fell by a third in a neighbouring town that put up no new lights.
- C In a similar neighbouring town with no new lights, night thefts stayed level over the same period.
- D Some residents complained that the lights were too bright.
Answer: C. C removes the rival explanation that thefts were falling everywhere anyway. B does the opposite: it weakens. A and D are beside the point.
Practise: Strengthen and Weaken Arguments · Causation Reasoning
4Weaken
“Which of the following, if true, most weakens the argument?”
- Method
- Attack the link, not the facts. In cause-and-effect arguments, look for reverse causation, a third factor, or coincidence.
- Trap
- An option that disagrees with the conclusion in tone but gives no reason to doubt it.
A survey found that students who use a study planner score higher in mocks than those who do not. Using a planner therefore raises scores.
Which of the following, if true, most weakens the argument?
- A Study planners are cheap and easy to find.
- B Students who already score well are more likely to start using a planner.
- C The survey covered students in five cities.
- D Some study planners are digital.
Answer: B. B says the scores may cause the planner, not the other way round. None of the others touches the causal claim.
Practise: Strengthen and Weaken Arguments · Causation Reasoning
5Inference
“Which of the following must be true?” or “can be inferred”
- Method
- Stay inside the passage. The answer follows from what is stated, without outside knowledge. Prefer the modest option over the sweeping one.
- Trap
- Something that could be true, or is probably true, but is not forced by the passage.
Every member of the debate club also belongs to the quiz club. Some members of the quiz club are in Class 12. Meera is in the debate club.
Which of the following must be true?
- A Meera is in Class 12.
- B Meera belongs to the quiz club.
- C Some debate club members are in Class 12.
- D Every quiz club member is in the debate club.
Answer: B. Meera is in the debate club, and every debate member is in the quiz club. The Class 12 members of the quiz club may all be outside the debate club, so A and C need not be true; D reverses the first statement.
Practise: Reading Comprehension: Inference Questions · Statement and Conclusion
6Flaw
“The reasoning is flawed because it…”
- Method
- Name the mistake before reading the options. The usual ones: treating correlation as cause, generalising from a few cases, attacking the person, a false choice between two options, and assuming what it sets out to prove.
- Trap
- An option describing a real flaw that this argument does not commit.
All three of our school’s toppers this year studied with music playing. Studying with music clearly helps students score well.
The reasoning is flawed because it:
- A assumes music is the only way to study well.
- B draws a general conclusion from three cases, without asking how other students who studied with music fared.
- C attacks the toppers rather than their method.
- D relies on the opinion of experts.
Answer: B. Three toppers are a tiny, hand-picked sample; students who studied with music and did badly are never counted. The argument does not claim music is the only way, attack anyone, or cite experts.
Practise: Flaws in Reasoning: Logical Fallacies
7Course of action
“Which of the following courses of action follow?”
- Method
- A course of action follows if it is practical, deals with the problem in the statement, and lies within the power of whoever must act. Extreme or unrelated steps do not follow.
- Trap
- A drastic step that would technically end the problem, at a cost out of proportion to it.
Statement: Several students in a hostel fell ill after eating at its canteen on Tuesday. Courses of action: I. Food samples from the canteen should be tested and its kitchen inspected. II. The hostel should be shut down permanently.
Which course(s) of action follow?
- A Only I
- B Only II
- C Both I and II
- D Neither I nor II
Answer: A. Testing and inspection go to the cause and are proportionate. Closing the hostel for good is out of all proportion to one bad meal.
Practise: Critical Reasoning: Course of Action
8If-then statements
Any passage built on “if”, “only if”, “unless” or “whenever”
- Method
- “If A, then B” gives you “if not B, then not A”, and nothing else. It does not give “if B, then A”, nor “if not A, then not B”.
- Trap
- Reversing the condition: hearing that the match was cancelled and concluding that it rained.
If it rains, the match is cancelled. The match was not cancelled.
Which of the following must be true?
- A It rained.
- B It did not rain.
- C The match was played in the evening.
- D It rained, but the match went ahead.
Answer: B. Rain would have cancelled the match; the match was not cancelled; so it did not rain. D contradicts the first sentence.
Practise: Conditional Reasoning: If-Then Statements · Assertion and Reason
