Must Be True Questions | CLAT Logical Reasoning

📑 On this page

⚡ The 20-second answer

A must be true option holds in every situation the passage allows. Test it: keep every sentence true and try to make the option false. If you can, it's out. The right answer is usually modest, often two sentences joined. The #1 trap: the option that is likely, not forced.

🎬 The 30-second story

The surprise inspection

“Warden's notice: every room on Floor 3 failed today's surprise inspection!”

📢

Rohan

7:02 a.m., hostel group chat.

“Meher's on Floor 3. So Meher's the messiest girl in the hostel. Called it.”

🧦

Aarav

Aarav, pre-chai.

“What must be true: Meher's room failed. That's it. Her roommate owns the socks.”

🖊️

Zoya

Zoya circles the word “every”.

“Also, three rooms on our floor failed only for broken fans.”

🌀

Meher

Meher, not amused.

Tara's verdict: A must-be-true answer survives every version of the facts. “Meher's room failed” survives them all. “Meher is messy” dies in the world where her roommate is the slob or the fan broke. One world where the facts hold and the option fails is enough to rule it out.

How does CLAT word must-be-true questions?

CLAT's version comes with a long opinion passage and the word necessarily. It is the strictest stem in the section: not “supported”, not “likely”, but forced.

The stem says	Seen in	What it asks
“Based on the author's arguments, which … must necessarily be true?”	CLAT 2023 Q110	What the author's claims force
“If the information in the passage above is correct, which … must necessarily be true?”	CLAT 2023 Q120, 2024 Q94	Grant every claim; what follows?
“Which can be inferred?”	Most CLAT years	A looser cousin
“Which CANNOT be true?” / “all EXCEPT”	Mocks and older papers	The option the passage contradicts

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📌 Grant the passage, then attack the option

Treat every claim in the passage as true, even ones you'd argue with. Your only job is to try to break each option without breaking the passage.

What makes an answer “must be true” and not just likely?

Picture every world the passage allows. A must-be-true option holds in all of them, not most. That's why the right answer feels dull: dull claims are hard to break.

🎚️ The scale

The certainty meter

← ForcedRuled out →

Must be true

Holds in every world the passage allows.

e.g. Meher's room failed.

Likely

Holds in most worlds.

e.g. Meher will get a warning.

Possible

Allowed, not pushed.

e.g. Meher's room was messy.

Contradicted

No world allows it.

e.g. Meher's room passed.

⭕ Venn check

Floor 3, drawn as sets

Statements

▸All Floor 3 rooms are Failed rooms
▸Some Floor 3 rooms are Broken-fan rooms

Conclusions

Some Failed rooms are Broken-fan rooms
✅ Definitely follows — Floor 3's broken-fan rooms sit inside the failed circle.
All Failed rooms are Floor 3 rooms
🤔 Possible, not certain — Other floors may have failed too.
Some Broken-fan rooms are not Failed rooms
🤔 Possible, not certain — A Floor 1 room with a broken fan may have passed.

shaded = empty× = at least one lives here

How do you solve a must-be-true question?

1
Lock the facts
Note what the passage commits to. A view it only reports (“critics say”) is not one of its facts.
2
Shrink the option
Cut it to its core claim. Circle the strength words: will, all, only, because, most.
3
Build a counter-world
Keep every sentence true and try to make the option false. One working world kills it.
4
Keep the survivor
The last option standing is your answer. It is usually modest, and often joins two sentences.

Which options look true but don't have to be?

🧩 At a glance

Six ways an option fakes certainty

🌍Real-world true

True in life, absent from the passage.

🎲Likely, not forced

“Will probably” isn't “must”. One counter-world sinks it.

📈Quantifier creep

The passage says some, may, often; the option says most, will, always.

🔁Reversed rule

“All toppers revise daily” doesn't make every daily reviser a topper.

🗣️Reported view

“Critics argue…” is someone's claim, not the passage's fact.

🧩Missed combination

The answer often joins two sentences. Checking one at a time misses it.

🧭 Decision flow

Does this option have to be true?

❓ Does it use only what the passage states or forces?

No →

Out: outside knowledge or a new claim

Yes ↓

❓ Is it no stronger than the passage (some stays some, may stays may)?

No →

Out: quantifier creep

Yes ↓

❓ Can you keep every sentence true and still make it false?

Yes →

Out: likely, not forced

No →

Must be true ✓

⚠️ Extreme words aren't automatically wrong

In CLAT 2024 Q94 the right answer says all the institutions of the State, because the passage hands duties to the government, a regulator, courts and schools. Judge strength against the passage, not in a vacuum.

Worked examples: valid or merely likely?

✍️ Worked example Warm-up ⏱ 30 sec

Kabir's Monday combo

Kabir's notice: “Every customer who ordered the chai-samosa combo on Monday got a free cookie. No customer who got a free cookie paid by card.” Which must be true?
(A) Every Monday customer paid by cash or UPI.
(B) No customer who ordered the combo on Monday paid by card.
(C) Card-paying customers disliked the combo.
(D) Everyone who got a free cookie ordered the combo.

1
Lock the facts: combo → cookie → no card. Chained, that is B.
2
Counter-world for A: a customer who skipped the combo and paid by card. Facts intact; A dies.
3
D reverses the first rule: cookies may have gone to others. C is out of scope.

Answer: B

⚡ The exam-hall shortcut

Chain the arrows. The answer is usually the two ends joined.

✍️ Worked example CLAT level ⏱ 75 sec

The four-day week trial

A Pune software firm trialled a four-day week for six months. Output per employee, measured in completed tasks, stayed level with the previous six months, while sick-leave days fell by a third. The firm hired no new staff during the trial and did not change its targets. Leadership concluded that the four-day week “costs us nothing” and will make it permanent. Rival firms are watching, but most say their client-facing teams could not work four days.
If the passage is correct, which must be true?
(A) The four-day week caused the fall in sick leave.
(B) On average, each employee completed more tasks per working day during the trial than in the previous six months.
(C) Most rival firms will reject the four-day week.
(D) The four-day week will cost the firm nothing in future.

1
Lock the facts: same tasks per employee over four days a week instead of five; sick leave down a third.
2
A is causal. Counter-world: a mild flu season cut sick leave anyway. Likely, not forced.
3
C creeps: “most say their client-facing teams can't” isn't “most will reject it”.
4
D is leadership's view, and a forecast. Reported, not proved.
5
B joins two facts: same output, fewer working days, so more tasks per day. No counter-world exists. Must be true.

Answer: B

⚡ The exam-hall shortcut

When three options are a cause, a forecast and somebody's opinion, look for the dull one built from two numbers.

✍️ Worked example Tricky ⏱ 45 sec

The half-marathon “cannot be true”

“Every hostel resident who joined the 6 a.m. running club in August ran the college half-marathon in December. Meher, a hostel resident, ran the half-marathon. No one who ran it had skipped the pre-race medical check.” Which cannot be true?
(A) Meher did not join the running club.
(B) Meher skipped the medical check.
(C) Some half-marathon runners never joined the club.
(D) Meher joined the club and ran the race.

1
Flip the job: three options are merely possible; one clashes with a fact.
2
A tempts you to say Meher must have joined. That reverses the rule. Possible.
3
C and D are allowed. Possible.
4
B: Meher ran, and no runner skipped the check. Clash. Cannot be true.

Answer: B

⚡ The exam-hall shortcut

On a CANNOT stem, ignore “likely” and hunt for a clash with one sentence.

How has CLAT asked must-be-true questions?

📝 Asked in CLAT 2023 · Q110 Following a causal chain

…This, in turn, has caused major central banks to raise interest rates, forcing investors back to the safe haven of the US dollar… Higher interest rates in developed country markets have caused a significant outflow of portfolio investments from India, aggravating the already climbing demand for dollars from a rising import bill… In the face of these pressures, the rupee, left to itself, would decline in value as the rupee-price of a dollar would increase substantially… [The Telegraph]

Based on the author's arguments, which of the following must necessarily be true?

AThe continuing depreciation of the Indian rupee at its current rate, coupled with worldwide inflationary trends, would result in immense political instability in India, and consequently, in all of South Asia.

BIf nothing else is done, the rise of interest rates in developed country markets, coupled with hardening of inflationary trends across the world, will result in a fall in the value of the rupee against the dollar.

CIf inflationary trends continue to harden across the world, and if interest rates in developed country markets continue to rise, portfolio investors will increase their investments in India, and this will have a positive impact on India's foreign exchange reserves.

DIf nothing else is done, the rise of interest rates in developed country markets, coupled with hardening of inflationary trends across the world, will result in a rise in the value of the rupee against the dollar.

Reveal answer + reasoning

Answer: B

Lock the chain: inflation → higher rates abroad → money leaves India → more demand for dollars → the rupee, left to itself, declines. B is that chain, with “if nothing else is done” standing in for “left to itself”. Try a counter-world: keep every sentence true and let the untouched rupee rise. You can't. Answer B. Time: 50 seconds.

Why the others fail

A — Political instability across South Asia is never mentioned: a new, far bigger claim.
C — Opposite: higher rates abroad pulled portfolio money out of India.
D — Opposite: left to itself, the rupee falls.

📝 Asked in CLAT 2024 · Q94 When “all” is right

…deciding how the coming changes should be regulated is very important. TRAI has made a strong case for an independent statutory authority to ensure the responsible development and use of AI in the country… In this and at this stage, a proactive government role is key, rather than just waiting on some large corporation to do the needful… This does not let other institutions off the hook. A US judge has rejected the copyright for an AI-generated artwork. Indian courts should start engaging with the broader issue of non-human agency rather than wait for precedence to be set elsewhere. Indian schools need to think beyond the ban-ChatGPT mindset. Let us lead instead of only being led. [Times of India]

If the information in the passage above is correct, which of the following must necessarily be true?

AAI regulation is the responsibility of the legislature alone.

BAI regulation is the responsibility of courts and can't be addressed through standalone statutory rules.

CAI regulation is a collaborative effort involving all the institutions of the State.

DAI regulation is the domain of private industry.

Reveal answer + reasoning

Answer: C

Lock the facts: a regulator wants a statutory authority, the government must act proactively, and “other institutions” aren't off the hook, so courts and schools must move too. Regulation is a shared job. C says so. Its “all” looks risky, but the passage itself spreads the duty across every institution it names. Answer C. Time: 40 seconds.

🔬 Option autopsy

Option autopsy: CLAT 2024 Q94

Which must necessarily be true?

A The responsibility of the legislature alone. Tag it

📢 Too strong / extreme

“Alone” clashes with roles for TRAI, courts and schools.

B The responsibility of courts; can't be addressed through statutory rules. Tag it

🔄 Opposite direction

A statutory authority is exactly what TRAI proposes.

C A collaborative effort involving all the institutions of the State. Tag it

✅ Correct

Government, regulator, courts, schools: a shared effort.

D The domain of private industry. Tag it

🔄 Opposite direction

The author wants action “rather than just waiting on some large corporation”.

📢 Too strong / extreme🔄 Opposite direction✅ Correct

Guess the trap behind each option, then tap to check. Wrong options fail in a handful of predictable ways.

Can you tell “must” from “maybe”?

💥 Myth vs fact

Myth vs fact: must be true

🙅 Myth

The answer that sounds most reasonable is right.

Tap to bust it →

✅ Fact

The answer that can't be broken is right.

🙅 Myth

Any option with “all” or “never” is wrong.

Tap to bust it →

✅ Fact

Only if the passage doesn't back it. 2024 Q94's answer says “all”.

🙅 Myth

If the author mentions a view, it's a fact you can use.

Tap to bust it →

✅ Fact

A view the author only reports (“critics say”) isn't the author's claim.

🙅 Myth

Must-be-true answers just repeat the passage.

Tap to bust it →

✅ Fact

Often they join two sentences into a new fact.

🎯 Quick quiz

Five “must” checks

0 / 5

Last season, every player in the college cricket squad who scored a century also made the inter-university team. No one in the inter-university team was older than 23. Aarav, the squad's opener, scored two centuries last season. The coach, Kabir, calls Aarav “the best batsman this college has ever produced”, and says Aarav will keep opening the batting next season.

Q1. If these statements are true, which must be true?

Q2. Some students at the CLAT seminar bought the new guide. Everyone who bought the guide got a free mock pass. Which must be true?

In March, the city's public libraries extended their opening hours to 10 p.m. Between March and June, visits after 6 p.m. doubled compared with the same months last year, while total visits rose by 15%. No new branches opened and membership fees did not change. The mayor said the longer hours had “brought reading back to the city” for good.

Q3. If the passage is correct, which must be true?

Q4. The passage says “many students prefer online mocks”. Which word in an option should worry you most?

Q5. All the night-canteen items are vegetarian. Some night-canteen items are fried. Which CANNOT be true?

🎯 Must be true in a nutshell

A must-be-true option holds in every world the passage allows.
Test: keep every sentence true and try to make the option false. One counter-world kills it.
Fakes: real-world facts, likely outcomes, quantifier creep, reversed rules, reported views.
The answer is usually modest and often joins two sentences.

📎 Cheat sheet

“Must necessarily be true” → must be true → build a counter-world for each option
“If the information is correct…” → grant every claim → attack options, not the passage
“Can be inferred” → inference → same test, slightly looser
“CANNOT be true” / “EXCEPT” → contradiction hunt → find the option that clashes with one sentence
Option has will, all, only, because → check the passage is that strong
Option joins two facts → strong candidate: check the arithmetic or the chain

Frequently asked questions

What is a must be true question in CLAT logical reasoning?

It asks which option the passage guarantees: true in every situation where the passage is true. CLAT words it “which of the following must necessarily be true?” It is stricter than “supported” or “likely”: if the passage can hold while the option fails, the option is wrong.

How do I solve must be true questions quickly?

Lock the facts the passage commits to, shrink each option to its core claim, then try to build a counter-world where the passage stays true and the option is false. If you can, eliminate it. The option you can't break is the answer.

Is a must be true question the same as an inference question?

Nearly. Both forbid outside facts and reward what the passage forces. “Can be inferred” is sometimes marked a little more loosely, as best-supported. “Must necessarily be true” is the strict version, so run the counter-world test on every option, with no exceptions.

Are options with extreme words always wrong in must be true questions?

No. All, only and never are wrong when the passage is weaker than the option. When the passage itself is that strong, the extreme option can be right, as in CLAT 2024 Q94. Compare the option's strength with the passage's.