Follow a one-way rule without inventing its converse.
Practise if, only if, not both and an explicitly inclusive or. The section reports answers, not a timed reasoning level.
A correct count describes six selected tasks in this section. It is not a reasoning rank or professional qualification. Every count opens all explanations and this complete guide.
Separate a rule from a prediction
These six questions supply rules that are assumed to hold in a fictional case. The task is to use those rules, not to judge whether a real machine or organization would behave reliably. Your count shows how many selected answers matched this edition. No speed test, supervised assessment or professional standard is part of the result. A low or high count therefore gives a place to review this particular notation and wording.
Translate before following the rule
For “if P, then Q”, write P to Q. P being true requires Q; Q being false rules out P. Q being true does not alone establish P, and P being false does not alone rule out Q. For “P only if Q”, Q remains necessary for P, so keep the same P-to-Q arrow. Write out the complete sentence again whenever the placement of “only” feels uncertain to you.
Acceptance need not identify its route
Imagine a rule saying that a checked sample receives a triangle sticker. You see a triangle sticker on a sample. The sample could have been checked, but the rule does not say that checking is the only route to the sticker. A second, unchecked sample could receive one through another permitted route. Both cases satisfy the one-way rule. If the problem instead stated “if and only if”, that extra reverse rule would change what follows.
Keep not both separate from neither
“Not both P and Q” allows P alone, Q alone, or neither; it excludes only the joint true case. “At least one” excludes neither but allows both, unless the question expressly says otherwise. When the wording combines these constraints, retain both parts instead of remembering only one. Do not replace “not open” with a richer description such as “broken”: a negation usually removes a state without supplying an explanation for it.
Use two possible cases to test uncertainty
For an undetermined claim, try describing one case where it is true and another where it is false, while preserving every premise. This is more useful than guessing from how probable the claim sounds. Compare your cases with the free item explanation, then try a new context. Public sharing links to a general guide and excludes your responses and correctness count. Memorizing this answer sequence cannot certify reasoning ability or predict an admissions or employer score.