LSAT Question Stem

The conclusion drawn above follows logically if which one of the following is assumed? 

Logical Reasoning Question Type

This is a Sufficient Assumption question. 

Correct Answer

The correct answer to this question is E. 

LSAT Question Complete Explanation

This LSAT problem is a Sufficient Assumption question, which is asking us to find the statement that, when combined with the premises, will make the conclusion a logical conclusion.

Let's first summarize and analyze the argument in the passage:

Premise: Having an efficient, attractive subway system makes good economic sense.

Premise: The city should always do what makes good economic sense.

Conclusion: The city needs to purchase new subway cars.

Now, let's create an "Evaluate" question for this argument: "Is purchasing new subway cars the only way to achieve an efficient and attractive subway system?"

Let's discuss each answer choice in detail:

a) The city should invest in an efficient, attractive subway system.

Incorrect. While this answer choice aligns with the premises, it does not specify that purchasing new subway cars is necessary for achieving an efficient, attractive subway system.

b) Cost-effective subway cars are an integral part of an efficient subway system.

Incorrect. This answer choice addresses "cost-effective subway cars," but the conclusion discusses "new subway cars." It doesn't establish that purchasing new subway cars is necessary.

c) Investment in new subway cars makes better economic sense than many of the other investment options open to the city.

Incorrect. This answer choice suggests that purchasing new subway cars is a reasonable decision, but it does not establish that it is necessary for the city to achieve an efficient, attractive subway system.

d) New subway cars are financially affordable.

Incorrect. Affordability is not the issue in the argument. The focus is on whether purchasing new subway cars is necessary for an efficient, attractive subway system.

e) New subway cars are required in order for the city to have a subway system that is efficient and attractive.

Correct. This answer choice implies that purchasing new subway cars is necessary for the city to achieve an efficient, attractive subway system. When combined with the premises, this statement leads to the conclusion that the city needs to purchase new subway cars.

In summary, the correct answer choice is (e), as it establishes that purchasing new subway cars is necessary for the city to achieve an efficient and attractive subway system, which aligns with the argument's conclusion.