Logical reasoning PrepTest 131 · Section 1 · Question 17

Incorrect. This answer discusses retooling a current process, which means the second conditional would have to justify it. That conditional allows us only to conclude that we shouldn't retool, however, so this answer is incorrect.

Incorrect. This answer discusses retooling a current process, which means the second conditional would have to justify it. However, it concludes that a retooling should happen, whereas that conditional only allows a conclusion to be drawn that a process shouldn't be retooled.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True (Principle)

Stimulus Summary:
(1) Two new processes about the same cost → Go with one less environmentally damaging
(2) (Already damaging environment AND Retooling would be a substantial cost) → (Should retool → Legally required OR Likely to bring long-term savings greater than that cost)

Answer Anticipation:
After reading that first principle, you may have thought this question wouldn't be too bad. But then that second principle . . .

There are several ways to diagram it, but we used parentheses to show that there's a joint sufficient condition (AND) that, when true, guarantees the truth of another conditional statement. So for the second condition to apply, the first sufficient condition must be met, and then we can apply the second conditional.

For Must Be True (Principle) questions, we generally want to ensure that the likely conclusion of the argument is in the necessary condition. For the first principle, that's already the case—arguments are likely to conclude that one process should be used over another, and that first principle already aligns with that.

The second principle, however, doesn't line up with that because we should expect the conclusion to be about whether or not the company should retool. So we need to work with that conditional in order to get it to conform to that argument structure.

How can we do that? Well, that nested conditional—the full conditional within the parentheses—has all the rules of a normal conditional. That includes the contrapositive being logically equivalent to the original statement. So we can take the contrapositive of just that part without changing the meaning of the statement:
Damaging AND Retooling expensive → (not Legally required AND not Likely to bring long-term savings → Shouldn't retool)

How can we get away with this? Think about it this way—one way to rephrase that conditional is, "Being legally required or bringing about long-term savings is a requirement for retooling," which is equivalent to saying, "If these requirements—legally required and likely to bring savings—aren't met, then retooling shouldn't happen." We haven't changed the meaning by taking the contrapositive, so we have an equivalent statement.

One last note, as we should always identify what conclusions can be justified based on the principles. Conditionals allow us to conclude the necessary condition when the sufficient is met, so the first allows us to conclude that we should adopt one of two processes under consideration. The second allows us to conclude that we shouldn't retool a currently existing process. No other conclusions can be validly drawn!

Now that we've got the principles in a structure that will likely align with the answer choices, we can head down to analyze them. And if the LSAT relies on the first principle for the correct answer, feel free to be justifiably upset at all the work it made you do on the second one!

Answer Explanation:
Since this answer features the consideration of two new processes, the first principle would be needed to justify it. The two processes are not substantially different in cost, which meets the sufficient condition of that principle, which justifies going with the less environmentally damaging process. Since this answer concludes that the less environmentally damaging process should be adopted, it's justified by that first principle and this is the correct answer. Without needing to understand the second one at all . . .

Key Takeaway:
The type of complex conditional that you see in the second principle here has only shown up a handful of times on the LSAT, and when that's happened, it hasn't actually led to a correct answer—it's been there to try to trap you in the incorrect ones. So don't worry too much if you're a little lost in it. That said, it's great practice—if you can make sense of it, the LSAT can't throw a conditional at you that you won't understand.

Incorrect. Since this answer features the consideration of two new processes, the first principle would be needed to justify it. The two processes are not substantially different in cost ("slightly cheaper"), which meets the sufficient condition of that principle, which justifies going with the less environmentally damaging process. However, this answer concludes that the more environmentally damaging but cheaper process should be adopted, so the principle doesn't justify this conclusion.

Incorrect. This answer discusses retooling a current process, so we should look to the second principle. However, that principle can't justify a conclusion that a process should be retooled, just that it shouldn't be, so this answer is incorrect.