Logical reasoning PrepTest 138 · Section 3 · Question 4

Incorrect. Very tempting answer. However, the stimulus notes that the cities with the most polluted air "30 years ago" have improved air quality today. It could be that the city with the worst air pollution today didn't have the most polluted air 30 years ago, and thus the stimulus doesn't guarantee pollution got better in this city since that statement from the stimulus doesn't apply.

Incorrect. The stimulus only discusses the effect that stricter regulations have had on the most polluted cities from 30 years ago, so it's possible that a city not in that category saw worsened pollution.

Incorrect. There's no indication of where the outcries came from, so this answer is unsupported.

Incorrect. Another tempting answer! However, just because the most polluted cities have seen "greatly improved" air quality doesn't mean that they're less polluted than other cities. They may have improved while still seeing a higher-than-average level of pollution.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Public pressure has resulted in emissions regulations
Cities with worst pollution 30 years ago are better now
not Stricter regulations → not Improvement in most polluted cities

Answer Anticipation:
These statements are all pretty strong and causal or conditional, and they share some terms, so we should check to see if we can make an inference.

The stimulus notes that there was public pressure that led to stricter regulations, and these regulations were necessary for the improvement in air quality in the most polluted cities. Putting those together, we can say that public pressure played a role in improving the air quality in these cities.

Answer Explanation:
This answer connects the premises together to form a valid conclusion based on the stimulus. If the improved air quality in the cities that had the worse air quality 30 years ago wouldn't have happened without the stricter regulations that were the result of the public outcry, we can infer that the public criticism played a role in that improved air quality.

Key Takeaway:
Statements that share a term are a key place to look for inferences in Must Be True questions. Much like rules that discuss the same term in LG lead to inferences there, this overlap frequently leads to inferences in LR.