Luiss Master's Admission Test cheat sheet

Main idea = the claim the whole passage is built to support; a true detail that supports only one paragraph is not the main idea.

Inference questions: the correct answer must be forced by the text, not merely plausible in the real world. Reject answers needing outside facts.

Scope words decide correctness: all, only, never, always, primarily, mainly. An answer that overstates the passage's claim is wrong.

Tone and attitude are signalled by adjectives and hedges (arguably, apparently, admittedly, regrettably), not by topic alone.

Passage structure markers: however, yet, although, despite signal contrast; therefore, thus, hence signal conclusion; for example signals illustration.

The author's conclusion usually follows a contrast marker or a causal marker, not the first sentence of the passage.

EXCEPT and NOT questions: three options are supported by the text; the answer is the one the passage contradicts or never addresses.

Analogy questions require matching the logical relation, not the topic: identify whether the pair is cause-effect, part-whole, or degree.

Vocabulary in context: substitute each option into the sentence and keep the one that preserves the passage's argument, not the most common dictionary sense.

Percent change = (new − old)/old × 100. A 20% rise followed by a 20% fall leaves a net 4% decrease, since 1.2 × 0.8 = 0.96.

Successive percentage changes multiply: total factor = (1 + r1)(1 + r2). Additive summing of percentages is a trap.

Work-rate: combined rate = 1/a + 1/b; time together = ab/(a + b).

Ratios: if a:b = 3:5, write parts as 3k and 5k, then use the given total or difference to solve for k.

Averages: total = average × count. Adding a value above the current average raises the average; the new average moves toward the added value.

Simple interest = P × r × t; compound interest = P(1 + r)^t − P. Compound exceeds simple whenever t > 1.

Probability of independent events multiplies: P(A and B) = P(A) × P(B). P(A or B) = P(A) + P(B) − P(A and B).

Geometry: area of triangle = ½bh; circle area = πr², circumference = 2πr; Pythagorean triples 3-4-5, 5-12-13, 8-15-17 appear often.

Number properties: a number is divisible by 3 if its digit sum is divisible by 3, by 9 if the digit sum is divisible by 9, by 4 if the last two digits form a multiple of 4.

Valid argument forms: modus ponens (If P then Q; P; therefore Q) and modus tollens (If P then Q; not Q; therefore not P).

Invalid forms: affirming the consequent (If P then Q; Q; therefore P) and denying the antecedent (If P then Q; not P; therefore not Q).

Necessary condition: Q is necessary for P means P → Q. Sufficient condition: P is sufficient for Q also means P → Q.

Contrapositive is logically equivalent to the original conditional; the converse and inverse are not.

Syllogism check: an argument with two premises about different groups yields a conclusion only if a shared middle term links them.

Assumption questions: the answer is the unstated premise the conclusion requires; negate it - if the argument collapses, it is the assumption.

Weaken questions: the answer makes the conclusion less likely without disproving the premises; attacking the evidence's representativeness is a common pattern.

Correlation does not establish causation; alternative explanations (reverse causation, third factor) are standard weakeners.

Ordering and grouping puzzles: draw a fixed diagram, place the most constrained item first, and test each option against all stated rules.

Law of demand: price and quantity demanded move in opposite directions, other things equal. Supply curves slope upward.

Equilibrium price clears the market; a price ceiling set below equilibrium creates shortage, a price floor above equilibrium creates surplus.

Price elasticity of demand = % change in quantity / % change in price. Demand is elastic when the absolute value exceeds 1.

Opportunity cost is the value of the best forgone alternative, not the sum of all alternatives.

GDP measures final goods and services produced within a country in a period; it excludes intermediate goods and transfer payments.

Inflation is a sustained rise in the general price level, reducing purchasing power; deflation is the opposite.

A central bank raises policy rates to cool inflation and lowers them to stimulate demand; higher rates raise borrowing costs.

Comparative advantage explains gains from trade: a country specializes where its opportunity cost is lower, even if it is less productive in absolute terms.

EU institutions: the European Commission proposes legislation, the European Parliament and Council of the EU legislate, the European Central Bank sets euro-area monetary policy.