A new gardening rake with an S-shaped handle

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsSufficient Assumption

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Stimulus

A new gardening rake with an S-shaped handle reduces compression stress on the spine during the pull stroke to about one-fifth of what it is with a straight-handled rake. During the push stroke, however, compression stress is five times more with the new rake than with a straight-handled rake. Neither the push Therefore, straight-handled rakes are better than the new rakes for minimizing risk of spinal injury.

What this question is testing

Sufficient Assumption

The Argument

The new S-shaped rake reduces compression stress on the pull stroke but spikes it dangerously high on the push stroke. The straight rake never reaches dangerous levels. Conclusion: the straight rake is safer.

Evaluate

The argument is comparing the two rakes only on compression stress. But "spinal injury" could come from many things — repetitive motion, twisting, lifting strain. If pull-stroke compression stress (or some other factor the new rake addresses) actually causes injuries, then the new rake might still be safer overall.

To get from to "the straight rake is safer," we have to assume push-stroke compression is the only kind of injury risk that matters. Otherwise the new rake could win on the other measures and still come out ahead.

Goal

The right answer should plug that gap — say something like "push-stroke compression is the only injury source" — so the conclusion follows logically.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question

20.

The conclusion above is properly drawn from the premises given if which one of the

Answer choices

Correct73% picked this
Compression stress resulting from pushing is the only cause of injuries to the spine that occur as
Why this is right
This is the assumption that makes the argument work. If compression stress from pushing is the only cause of raking-related spinal injuries, then the new rake (which puts pushing stress above the danger level) is the only one that causes injury, while the straight rake (which never reaches the danger level) does not. The conclusion that the straight rake is safer follows directly. Without this assumption, other injury sources could matter and the new rake might come out ahead.
Skill tested: Sufficient Assumption · how this choice captures the argument's function is the move to repeat next time.
73%
Out of Scope6% picked this
Raking is a frequent cause of spinal injury
How frequent raking-related spinal injuries are among gardeners does not affect which rake is safer. Even if injuries are rare, one rake can still be safer than the other. The conclusion is comparative, and frequency does not bridge the comparison.
6%
Out of Scope8% picked this
The redesign of a tool rarely results in a net gain of efficiency, since gains tend to
This is a sweeping claim about tool redesigns in general. The argument is about a specific spinal-injury comparison. Whether or not redesigns usually involve trade-offs does not give us the missing link between the compression stress data and the safety conclusion. The argument needs an assumption about what causes injury, not about redesigns in general.
8%
No Impact9% picked this
A garden rake can never be used in such a way that all the strokes with that
This says you cannot use a rake using only push strokes. That is true (you have to pull at some point), but it does not close the gap. The argument's issue is whether pushing is the only injury source — not whether pushing is the only stroke type. Even if both strokes happen, we still need to know whether pull-stroke factors (or non-compression factors) matter for injury.
9%
Out of Scope4% picked this
It is not possible to design a garden rake with a handle that is other
The argument is comparing two specific rakes, not surveying every possible handle design. Whether other designs could exist is irrelevant to whether the straight rake is safer than the new S-shaped rake. This does not close the injury-source gap.
4%

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