PrepTest 159, Section 3, Question 18
Jack's dog howls whenever a train goes by.(22 more words not shown)
The pattern of reasoning in(15 more words not shown)
- AEvery serious jogger(37 more words not shown)
- BMost serious joggers(32 more words not shown)
- CAny serious jogger(33 more words not shown)
- DAt least some(36 more words not shown)
- EAny serious jogger(33 more words not shown)
Reading the argument
On any occasion when a train goes by, the dog howls. If a train goes by during a bath, the dog therefore howls during that bath. The passage tells us that this sometimes happens, so the conclusion follows.
What we’re looking for
We don't know that the dog howls during every bath. We only know about the occasions when a train passes while Jack is washing it. For the parallel, keep those pieces separate: a rule that always connects a train with howling, some overlap between trains and washing, and a conclusion that howling and washing sometimes overlap.
Working the answers
- A
The first rule works: serious joggers can benefit from good shoes. But the other premise only tells us that some people who can benefit prefer ordinary sneakers. Those people could be casual joggers. We can't work backward and conclude that any of them must be serious joggers. In the original, we know the train passes during some baths; we don't infer a train from the dog howling during a bath.
- B
“Most” weakens the rule we need. If most serious joggers benefit from good shoes, the serious joggers who prefer ordinary sneakers might all fall outside that majority. We couldn't guarantee that any of them benefit. The dog's howling rule has no such exception: whenever a train passes, the dog howls.
- CCorrect
The answers switch to joggers and shoes, which can make the pattern harder to see. Don't reject an answer just because “ordinary sneakers” initially seems unrelated to the rule about good running shoes. The original also has a third idea: washing the dog. The job is to find which group or situation plays each role, not to require the topics themselves to resemble trains and baths.
Being a serious jogger corresponds to a train passing: it guarantees the next feature. Benefiting from good running shoes corresponds to the dog howling. Preferring ordinary sneakers corresponds to washing the dog, the third feature that overlaps with the first.
Some serious joggers prefer ordinary sneakers. Every one of those serious joggers can benefit from good shoes. So some people who benefit from good shoes prefer ordinary sneakers. That's the same valid connection as the train sometimes passing during a bath and thereby guaranteeing howling during some baths. Once we assign ordinary sneakers the washing role, the apparent mismatch disappears.
- D
This gives us some serious joggers who benefit and some serious joggers who prefer ordinary sneakers. They could be entirely different people. Without the universal rule that every serious jogger benefits, the two groups need not overlap. The original's always-howls rule supplies exactly that guarantee.
- E
The premises resemble C, but the conclusion reaches too far. Some serious joggers' preferences can't establish that anyone who benefits from good shoes prefers ordinary sneakers. The original only concludes that howling and washing sometimes coincide. It doesn't expand a few overlapping cases into a claim about everyone.
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