Logical reasoning PrepTest 117 · Section 2 · Question 13

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
Environmental problem solved AND not Result of government mismanagement → Major changes to consumer habits
Major changes to consumer habits → Changes are economically enticing
Conclusion — not Changes are economically enticing → Few serious ecological problems solved

Answer Anticipation:
This is a very wordy stimulus, but it has conditional language in it (only", "only if", "unless"), and conditional logic is frequently tested in Strengthen with Sufficient Premise questions, so we should get to diagramming!

The second and third conditionals are more straightforward (though we diagrammed "unless" as "if not"—you may have the contrapositive, which is fine!), but the first one we should dig into a bit. When a conditional term takes the form of "All A that are not B, what it's saying is All things that are A and not B." So it can be diagrammed more cleanly as an AND statement, as we did here.

With that in mind, let's take a look at the statements. There is some overlap between the premises and conclusion in that both discuss changes that are economically enticing and there are problems being solved, but the terms are negated, so let's get them to match up by taking contrapositives while chaining the premises together:
not Changes are economically enticing → not Major changes to consumer habits → not Environmental problem solved OR Result of government mismanagement

The premise chain and conclusion start off in the same place, and they end in similar but distinct locations.

The premise chain, if changes aren't made economically enticing, would allow it to be concluded that either the environmental problem isn't solved or the problem is a result of government mismanagement. The conclusion ends with the problems not being solved.

So there's a big difference between the two! The premises leave open a possibility that the conclusion doesn't—that the problem was the result of government mismanagement. To ensure that the other potential OR condition can be concluded, as this argument does, we therefore have to rule out that possibility. Let's find an answer stating that few (to match the conclusion) serious ecological problems are the result of government mismanagement.

(Note that the premise does use the term environmental and the conclusion ecological, but it's unlikely that the LSAT is going to test your knowledge of subtle differences between these fields of science without defining them. In any case, ecological problems are a subset of environmental ones.)

Answer Explanation:
The conditional chain in the premises leads to two potential necessary conditions (OR)—problems not solved, or problems related to government mismanagement. Since the conclusion just deals with the former, it assumes that the latter doesn't happen often. This answer establishes that, so it's correct.

Key Takeaway:
Strengthen with Sufficient Premise questions are frequently conditional, so diagram them out when you can! And when you see an OR statement, expect the answer to deal with one of the two options.

Incorrect. This answer is essentially a negation of the premise chain with a term shift between economically enticing and economically feasible—two reasons to rule it out.

Incorrect. The argument is completely conditional, whereas this answer makes one of the terms actually happen. If the conclusion weren't conditional, then we would need an absolute statement to trigger the conditional; since it's conditional, we don't!

Incorrect. This answer doesn't speak to the prevalence of these problems that are and aren't the result of government mismanagement, which is what's missing from the argument.

Incorrect. This answer choice, if true, draws a distinction between major environmental problems and ecological ones, but the argument treats them as interchangeable.