#23 - Male boto dolphins often carry objects such as weeds

[Administrator]

Complete Question Explanation

Parallel Reasoning, SN. The correct answer choice is (D).

This Parallel Reasoning question offers a perfect example of how to use the Elemental Attack as there are two notable features in the stimulus:

• 1. The conclusion uses the the distinctive term "likely.
  
  2. The argument features a contrapositive on the way to making the conclusion.

Given the power of the contrapositive here, using this as your main weapon of elimination is the best choice, and the "likely" in the conclusion can then be used if and when it applies.

So, let's start by understanding the conditional relationship in the stimulus:

• Premise: Play (rather than mating) Females and Juveniles would do it expect
  
  Premise: Females and Juveniles would do it = "only males do"
  
  
  Conclusion: Play likely

The key to seeing this contrapositive is that "only adult males do" is equivalent to "neither females not juveniles do," which is the negation of the necessary condition. Second, because the conditional relationship used "expected," that reasonable allows the author to lower the force of the conclusion to "likely."

Now, look speedily for a contrapositive (this shouldn't require diagramming everything, you should be able—once you are done studying—to see it in the abstract) and watch the language in the conclusion.


Answer choice (A): The conclusion in this answer has a different level of force ("will") than does the conclusion, so immediately this answer is suspect. Further, this argument contains a Mistaken Negation instead of a contrapositive. Thus, this answer choice is incorrect.

Answer choice (B): This answer choice is in the form of a Restatement. The author states that if the tree is diseased, then it will be cut down. And the first premise indicates that the expectation is that the tree will be found diseased. Thus, the conclusion follows from that relationship. No contrapositive is used and the premise uses different language than the premise in the stimulus, making this answer less attractive despite a similar conclusion to the stimulus.

Answer choice (C): This argument contains a Mistaken Reversal instead of a contrapositive. Thus, this answer choice is incorrect.

Answer choice (D): This is the correct answer choice. This answer contains a contrapositive, as well as similar language across the premises and conclusion. Thus, it is correct.

Answer choice (E): Like answer choice (B), this answer is in the form of a Restatement and not a contrapositive:

• Premise: Big Sale Celebrate tonight
  
  Premise: Big Saleprobably
  
  
  Conclusion: Celebrateprobably

[tfab]

Can I get an explanation on why Answer (D) is the correct answer? I chose A during the practice test after briefly going through the answers. Not a fan of these questions at all so I usually speed through them or leave them for last. Any strategies on how to get better at them would be much appreciated as well. Thanks!

[Dave Killoran]

Can I get an explanation on why Answer (D) is the correct answer? I chose A during the practice test after briefly going through the answers. Not a fan of these questions at all so I usually speed through them or leave them for last. Any strategies on how to get better at them would be much appreciated as well. Thanks!

Hi tfab,

I've added a complete explanation above. This is an excellent problem, so spend some time with it until you have really Perfected how this problem works!

For more info on how to use our methods to solve Parallel questions (which get way easier once you know how), see the LSAT Logical Reasoning Bible, our LSAT courses, or Episode 4 from our podcast (less comprehensive than the other two but still useful).

Thanks!

[Ari]

Despite the explanation above, I am still having trouble ruling out choice A. I thought that the "So in all likelihood" made the conclusion of answer choice A less strong and more in line with the stimulus. Choice D I chose the first time through, so I understand it being correct. Is "in all likelihood" stronger than "probably?" Also, can someone please point out the mistaken negation?

[Jeremy Press]

Hi Ari,

The common reading of the phrase "in all likelihood" is intensified beyond just "likely." It may not quite reach to the level of certainty, but it goes higher than mere probability. So there's definitely a bit stronger conclusion in answer choice A than in the stimulus.

Nevertheless, even if you're unsure about how strongly to read "in all likelihood," answer choice A does have a clear Mistaken Negation. Here's what it looks like:

Premise 1: A Lot of Traffic (probably) Late
Premise 2: A Lot of Traffic {NOTE: the meaning of "I expect light traffic" is "I expect there NOT to be a lot of traffic}
Conclusion: (very probably) Late

Notice how the second premise is the negation of the sufficient condition. The author then concludes that the necessary condition is highly likely to be negated as well. That's the classic "Mistaken Negation" structure (Because a sufficient condition didn't happen, therefore its necessary condition also won't happen).

I hope this helps!