Flawed ReasoningDiff: Medium
Logic Breakdown
Passage Summary: Two kids who play together have the same symptoms, so the author assumes they have the same illness. Since one kid tested negative for strep, the author concludes the other kid definitely doesn't have it.
Conclusion: It is certain that Sara does not have a streptococcal infection.
Reasoning: Sara and Michael play together and share symptoms, so they likely have the same illness; because Michael definitely does not have strep, Sara must not have it either.
Analysis: The argument suffers from a classic 'probability to certainty' flaw. It starts with a reasonable premise—that Sara *probably* has what Michael has—but then treats that probability as an absolute fact to reach a 'definite' conclusion. Even if there is a 99% chance they have the same illness, there is still a 1% chance Sara has strep while Michael has a very similar-looking flu. The tutor's advice here is to watch for that shift in modal strength; you cannot turn a 'maybe' into a 'definitely' just because it makes the story cleaner.
Conclusion: It is certain that Sara does not have a streptococcal infection.
Reasoning: Sara and Michael play together and share symptoms, so they likely have the same illness; because Michael definitely does not have strep, Sara must not have it either.
Analysis: The argument suffers from a classic 'probability to certainty' flaw. It starts with a reasonable premise—that Sara *probably* has what Michael has—but then treats that probability as an absolute fact to reach a 'definite' conclusion. Even if there is a 99% chance they have the same illness, there is still a 1% chance Sara has strep while Michael has a very similar-looking flu. The tutor's advice here is to watch for that shift in modal strength; you cannot turn a 'maybe' into a 'definitely' just because it makes the story cleaner.
Passage Stimulus
Passage Redacted
Unlock Full Passage1.The reasoning in the argument is flawed because the argument
Correct Answer
D
The argument takes a probabilistic premise (Sara probably shares Michael’s illness) and uses it to reach a certain conclusion (Sara definitely does not have strep). Treating evidence that makes something likely as if it proved the conclusion with certainty is exactly the flaw described in D.
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