COLMILAV Prueba de Suficiencia common mistakes
COLMILAV Prueba de Suficiencia · Understand the traps and how to avoid them.
Solving a word problem by grabbing the numbers and applying whichever operation comes to mind, without first writing down what is being asked and what units the answer needs.
Under time pressure, candidates pattern-match on keywords ("total" means add, "left" means subtract) instead of modelling the situation, so they answer a question that was never asked.
What to do instead
Before computing, write one line: "Find: ___ in units of ___." Then list the given quantities with units. Only after that choose an operation and check the result against the units and against an estimate.
Treating a physics problem as a formula-hunt: scanning the equation sheet for one formula that contains all the given symbols, then substituting without checking whether the conditions of that formula hold.
Many candidates memorise formulas as symbol strings rather than as statements with preconditions (constant acceleration, no friction, ideal gas, closed system), so they apply them outside their validity range.
What to do instead
For each formula used, state its condition in words before substituting (e.g. "valid only if acceleration is constant"). If the condition is not met, split the problem into stages or use an energy/impulse argument instead.
Reading a passage once at speed and answering from memory or general knowledge rather than returning to the text to locate the line that supports the chosen option.
Candidates trust familiarity with the topic and confuse "sounds true" with "is stated or implied in the passage", which is exactly the trap distractor options are built on.
What to do instead
For every answer, point to the sentence or paragraph that justifies it. If no line supports it, the option is wrong even if it is factually true in the world.
Choosing an inference option that goes further than the passage, e.g. turning "some" into "all", "may" into "will", or a correlation into a cause.
Strong, confident-sounding options feel like better answers, and candidates do not track quantifiers and modal verbs while reading options.
What to do instead
Circle the quantifier and modal verb in each option (all/some/most; must/may/cannot). Eliminate any option whose strength exceeds what the passage supports, even if the direction of the claim is right.
In English items, translating the sentence word by word into Spanish and then judging whether the translation sounds natural, instead of applying the grammatical rule the item is testing.
Literal translation produces interference from Spanish structures (e.g. omitting the subject, wrong preposition, present where English needs present perfect), and the candidate's ear is tuned to the wrong language.
What to do instead
Name the point being tested first (tense, preposition, article, word order, false friend). Decide using the English rule, then read the full sentence aloud in English only to confirm.
Answering English vocabulary items by picking the option that looks similar to a Spanish word, without checking whether the English word actually carries that meaning.
False friends (actual, assist, realise, library, sensible) are frequent in Spanish-speaker exams, and surface similarity feels like recognition.
What to do instead
Keep a personal false-friend list and, in the exam, test each candidate option inside a short English sentence. If the sentence's meaning changes, the option is wrong.
Placing historical events, works, or authors in the wrong century or country because the candidate remembers a name but not its context.
General-culture material is usually studied as isolated name-date pairs, so similar figures and neighbouring periods blur together under recall pressure.
What to do instead
Build a single mental timeline and map each fact to a century plus a country or movement. When unsure, reason from a known anchor event rather than guessing freely.
In logic items, accepting a conclusion that merely repeats a premise or that reverses a conditional (from "if P then Q" concluding "if Q then P"), because the conclusion feels connected to the premises.
Candidates evaluate arguments by plausibility and topic coherence rather than by validity, so familiar-sounding but invalid forms pass unnoticed.
What to do instead
Rewrite the argument in symbols (P, Q, not-P, not-Q) and check only the form. Memorise the two valid conditional patterns (affirming the antecedent, denying the consequent) and reject their reverses.
On spatial-aptitude items, rotating or folding the figure mentally all at once and answering from the resulting impression, without tracking a single reference point.
Whole-figure mental rotation exceeds most people's working memory, so details such as which face is opposite or which edge meets which are lost silently.
What to do instead
Anchor one marked point or edge and track it step by step, drawing the intermediate state on scratch paper. For folding, label faces before folding and check adjacency, not just shape.
Spending disproportionate time on one hard item while leaving easier items at the end unanswered, and changing correct first answers on a hunch during review.
Sunk-cost pressure on a single problem plus anxiety about the clock leads to poor allocation, and review-time second-guessing often overrides solid reasoning.
What to do instead
Adopt a fixed pass rule: skip any item unsolved after its allotted share of time, mark it, and return only after finishing the section. Change an answer only when a concrete new reason is written down.