PrepTest 140, Section 1, Question 17
If a motor is sound-insulated, then it is(42 more words not shown)
If the statements above are(9 more words not shown)
- AIf a motor(10 more words not shown)
- BNone of the(7 more words not shown)
- CAt least some(13 more words not shown)
- DIf a motor(12 more words not shown)
- ENone of the(11 more words not shown)
Reading the argument
If an EM motor were sound-insulated, it would be quiet enough for a home appliance. But none of EM's motors are that quiet. So none can be sound-insulated.
That's the first rule doing the work: insulation guarantees the required quietness. An insulated EM motor would contradict what we're told about every EM motor.
What we’re looking for
Now keep the second rule separate. Being quiet enough for a home appliance is one way to qualify for institutional use. It doesn't say institutions accept only motors that quiet. A noisy motor might still be useful somewhere noise doesn't pose the same problem. For the must-be-true question, the firm prediction is no insulation on EM's motors; their eligibility for institutional use remains unsettled.
Working the answers
- A
Sound insulation would get us a motor quiet enough for home appliances, which would also qualify it for institutional use. But this answer starts at institutional use and demands insulation. There could be other ways for a motor to qualify. The rules never make insulation a requirement for every institutional motor.
- BCorrect
Suppose one of EM's motors had sound insulation. The first rule would make it quiet enough for home appliances. The final statement says no EM motor is quiet enough, so that supposition cannot fit the facts. None of the company's motors are sound-insulated.
- C
Some EM motors might qualify for institutional use, but we haven't been told that any do. The rule guarantees institutional use for sufficiently quiet motors, and EM's motors don't meet that description. Other routes may exist, but their mere possibility doesn't establish that an EM motor takes one.
- D
A motor could be quiet because it produces little noise in the first place, without needing insulation. The passage tells us insulation produces enough quietness; it doesn't say every quiet motor must have insulation. D adds a requirement the rule never supplied.
- E
We also cannot conclude that all EM motors are ruled out of institutional settings. A setting might tolerate a noisy motor that does the needed work. C and E make opposite claims about institutional use, but neither is established. What we do know is that the motors lack the insulation that would have guaranteed home-level quietness.
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