60-second revision
- An assumption is an unstated belief the speaker must hold for the statement to make sense.
- Negation test: deny the assumption; if the statement then becomes pointless, the assumption is implicit.
- Advice, requests and notices assume the action is possible and useful.
- Advertisements assume people want the product and that advertising works — never that rivals are useless.
- Extreme words (only, all, always, never, best, must) usually make an assumption NOT implicit.
- "If P then Q" with Q false gives "not P". With Q true, nothing follows about P.
- Use only the facts given, not outside knowledge or personal opinion.
What counts as an assumption
An assumption is something the speaker takes for granted without saying it. It is not a conclusion drawn from the statement, and it is not just any true fact. A notice "Wear helmets while riding" assumes that helmets reduce injury and that people ride two-wheelers; it does not assume that all riders are careless.
The negation test
Turn the assumption into its opposite and ask: does the statement still make sense? If the statement becomes pointless, the assumption is implicit. If it still stands, the assumption is not implicit.
| Statement | Assumption | Negated | Implicit? |
|---|---|---|---|
| Switch off fans when leaving the room. | Switching off saves electricity. | Switching off saves nothing. | Yes — the advice becomes pointless |
| Switch off fans when leaving the room. | People forget to switch off fans. | Nobody ever forgets. | Yes — no need for the reminder |
| Switch off fans when leaving the room. | Electricity is very costly in this city. | Electricity is cheap. | No — saving still makes sense |
Common statement types
| Type | Usually implicit | Usually NOT implicit |
|---|---|---|
| Advice or request | The action is possible and will help | The listener is foolish or careless |
| Government decision | There is a need, and the step will help | The step will solve the problem fully |
| Advertisement | People want this; ads influence buyers | Rival products are useless |
| Notice or warning | The danger is real; people read notices | Everyone always breaks rules |
| Appeal for funds | People will respond to appeals | The fund will reach a fixed target |
Worked example
Statement: "The railways will run ten extra trains on this route during the festival season." I. Many more people travel on this route during the festival season. II. The extra trains will remove all waiting lists. Test I: if festival travel did not rise, the extra trains would be pointless — so I is implicit. Test II: the plan still makes sense even if some waiting lists remain; "all" is an extreme claim — so II is not implicit. Answer: only I.
Drawing inferences from facts
Some questions give facts and ask what definitely follows. Stick strictly to the information. A conclusion must be forced by the facts; "probably true" is not enough unless the options say "may".
If-then reasoning — valid and invalid moves
| Given | Valid conclusion? | Why |
|---|---|---|
| If P then Q; P is true | Q is true — valid | The condition is met |
| If P then Q; Q is false | P is false — valid | Contrapositive |
| If P then Q; Q is true | Nothing about P | Q may have another cause |
| If P then Q; P is false | Nothing about Q | Q may still happen |
Example: "If the train is late, Sunil misses his class." Sunil did not miss his class → the train was not late (valid). Sunil missed his class → the train may or may not have been late (he could have overslept).
"Every A is B" works the same way: "every member of the choir can sing" means a person who cannot sing is not a member. But a person who can sing need not be a member.
Elimination with given categories
If the facts say every item is one of a few types and rule out some types, the remaining type is forced. "Each box is wooden or metal; no metal box is in the store-room" means a box in the store-room is wooden.
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