LSAT Explanation PT 23, S3, Q9: If a person chooses to walk

LSAT Question Stem

Which one of the following, if true, most strengthens the argument? 

Logical Reasoning Question Type

This is a Strengthen question. 

Correct Answer

The correct answer to this question is B. 

LSAT Question Complete Explanation

Let's break down the argument in the passage. The passage states that if a person chooses to walk rather than drive, there will be one less vehicle emitting pollution. The conclusion drawn is that if people walk whenever feasible, pollution will be greatly reduced. In this argument, the premise is that walking instead of driving reduces the number of vehicles emitting pollution, and the conclusion is that walking whenever possible will greatly reduce pollution.

Now, let's create an "Evaluate" question for this argument: "Does reducing the number of vehicles on the road significantly reduce pollution levels?"

The question type for this LSAT problem is Strengthen, which means we are looking for an answer choice that strengthens the argument.

Let's analyze each answer choice:

a) This answer choice doesn't strengthen the argument because it states that if automobile passengers who never drive walk instead of ride, there will not be fewer vehicles on the road. This doesn't provide any additional support for the conclusion that walking whenever feasible will greatly reduce pollution.

b) This answer choice strengthens the argument because it provides additional information about how reducing the number of vehicles on the road can lead to reduced pollution. It states that nonmoving running vehicles emit less pollution than moving vehicles, but congestion increases the number of nonmoving running vehicles. Therefore, if people walk and reduce the number of vehicles on the road, there will be less congestion and fewer nonmoving running vehicles, which in turn reduces pollution.

c) This answer choice doesn't strengthen the argument because it only provides information about individual drivers' contributions to pollution prevention. The fact that some drivers can contribute more to pollution prevention than others doesn't provide additional support for the conclusion that walking whenever possible will greatly reduce pollution.

d) This answer choice doesn't strengthen the argument because it talks about buses and their pollution levels compared to cars. The argument is about people walking instead of driving to reduce pollution, so information about buses is not relevant to the conclusion.

e) This answer choice weakens the argument because it suggests that if a driver decides to walk instead of drive, their passengers might decide to drive themselves, which could increase the number of vehicles on the road and pollution levels.

The correct answer is B, as it provides additional information about how reducing the number of vehicles on the road can lead to reduced pollution levels, thus strengthening the argument.