Examkin

Question

Difficulty: EasyIdentifying Sufficient Assumptions

Urban planners generally agree that any city that invests heavily in its public transportation infrastructure will inevitably experience a significant decrease in traffic congestion on its major roadways. Over the past two years, the city of Metroville has been making unprecedented financial investments to expand its light rail and citywide bus networks. Therefore, residents can be confident that the overall air quality in Metroville will soon improve.

Which one of the following, if assumed, enables the argument's conclusion to be properly drawn?

  1. Any city that experiences a significant decrease in traffic congestion on its major roadways will also see an improvement in its overall air quality.Answer
  2. B
    A significant decrease in traffic congestion on a city's major roadways is required for that city to see an improvement in its overall air quality.
  3. C
    If a city's overall air quality improves, it is because that city has invested heavily in its public transportation infrastructure.
  4. D
    Cities that do not invest heavily in public transportation infrastructure will not experience an improvement in their overall air quality.
  5. E
    The majority of cities that experience a significant decrease in traffic congestion on their major roadways also see an improvement in their overall air quality.

Answer

The correct answer is the statement bridging the gap by showing that a decrease in traffic congestion guarantees an improvement in air quality.
The argument concludes that Metroville's air quality will improve based entirely on the premise that it is investing in public transportation, which reliably decreases traffic congestion. There is a logical gap between the concept of 'decreasing traffic congestion' and the concept of 'improving air quality'. The correct choice successfully bridges this gap by establishing that a decrease in traffic congestion is strictly sufficient to guarantee an improvement in air quality. When added to the premises, this ensures the conclusion is a 100% valid deduction.

Step-by-Step Solution

1
Identify the conclusion of the argument.
Conclusion: The overall air quality in Metroville will soon improve.
This is the final claim the author is trying to prove, indicated by the word 'Therefore'.
2
Identify the premises supporting the conclusion.
Premise 1: Investing in public transit -> Decrease in traffic congestion. Premise 2: Metroville is investing in public transit.
These are the stated facts used to build the argument.
3
Find the logical gap between the premises and the conclusion.
The premises prove that Metroville will have a decrease in traffic congestion. However, the conclusion jumps to claiming an improvement in air quality.
A sufficient assumption must perfectly bridge the new term in the conclusion (air quality) back to the established premises (traffic congestion).
4
Formulate the necessary bridge.
We need a statement that says: If a decrease in traffic congestion occurs, then air quality will improve.
Adding this statement guarantees the conclusion is 100% true based on formal logic.

Key Concept

Sufficient Assumptions (Formal Logic Bridging)
Rate this question

Topics

Identifying Sufficient Assumptions

More questions from this topic