FSOT Logical Reasoning Sample Questions (Worked Examples)

These five examples illustrate the most common Logical Reasoning question types on the redesigned FSOT. Each example shows the stimulus, the question stem, the correct answer, and — most importantly — the reasoning path that gets you there. Practice the reasoning out loud before checking the answer.

Example 1: Inference

Stimulus: "Every diplomat at the Vienna conference signed the protocol. The U.S. ambassador did not sign the protocol. Some attendees of the conference were not diplomats." Question: Which of the following must be true? Correct answer: The U.S. ambassador was not a diplomat at the Vienna conference. Reasoning: If every diplomat signed and the ambassador did not sign, the ambassador cannot have been a diplomat at the conference. The third sentence is a distractor — it tells us non-diplomats attended, which is consistent with but does not establish the conclusion.

Example 2: Strengthen

Stimulus: "Countries that adopted floating exchange rates after 1971 grew faster on average than countries that maintained fixed rates. Therefore, floating exchange rates promote growth." Question: Which finding, if true, would most strengthen the argument? Correct answer: Within the countries that switched to floating rates, growth accelerated in the years immediately following the switch. Reasoning: The argument is vulnerable to reverse causation (maybe fast-growing countries chose floating rates). Within-country evidence that growth changed after the policy change directly addresses that gap.

Example 3: Weaken

Stimulus: "Students at Embassy School score higher on standardized tests than students at neighboring schools. Embassy School's smaller class sizes must explain the gap." Question: Which of the following, if true, would most weaken the argument? Correct answer: Embassy School admits students selectively, while the neighboring schools accept all applicants. Reasoning: The argument assumes the student populations are comparable. Selective admission introduces the most plausible alternative explanation — selection effect — which directly undermines the causal claim about class size.

Example 4: Assumption

Stimulus: "The new visa policy will reduce wait times because it allocates more interview slots to consulates with the longest backlogs." Question: Which assumption is the argument relying on? Correct answer: Consulates with the longest backlogs can effectively use additional interview slots. Reasoning: Apply the negation test. If consulates with long backlogs cannot use additional slots (because they're constrained by staffing, not slots), the policy won't reduce wait times. The argument collapses. Therefore the unstated assumption is the one above.

Example 5: Flaw

Stimulus: "Most countries that joined NATO after 1999 had been part of the Warsaw Pact. Therefore, joining NATO is part of a natural progression for former Warsaw Pact countries." Question: The argument is most vulnerable to which criticism? Correct answer: It treats a statistical pattern as evidence of a natural or inevitable trend. Reasoning: The flaw is naturalistic — describing what happened and then claiming it was "natural" or inevitable. Many former Warsaw Pact countries did not join NATO (Russia, Belarus); the pattern is selective, and the inference from "many did" to "it's natural" is unsupported.

How to use these examples

Re-do each one tomorrow without looking at the explanation. If you can re-derive the right answer and articulate why it's right, the pattern is sinking in. If you can't, the gap is in pattern recognition, not effort — switch to Drill Mode and do 20 of that question type in a row.