LSAT Explanation PT 28, S3, Q19: On a certain day, nine scheduled

LSAT Question Stem

The argument depends on which one of the following assumptions? 

Logical Reasoning Question Type

This is a Necessary Assumption question. 

Correct Answer

The correct answer to this question is A. 

LSAT Question Complete Explanation

First, let's analyze the argument in the passage. The argument states that on a certain day, nine scheduled flights on Swift Airlines were canceled. The argument then provides a premise: Ordinarily, a cancellation is due to mechanical problems with the airplane scheduled for a certain flight. The argument concludes that since it is unlikely that Swift would have mechanical problems with more than one or two airplanes on a single day, some of the nine cancellations were probably due to something else.

To make the argument more understandable, let's use a simple example. Imagine a school bus company that usually cancels bus routes due to mechanical problems with the buses. If nine bus routes are canceled on a single day, and it's unlikely that the company would have mechanical problems with more than one or two buses on a single day, then some of the cancellations were probably due to something else, like bad weather or a driver shortage.

An "Evaluate" question for this argument could be: "How many airplanes were scheduled for the nine canceled flights?"

Now, let's discuss the answer choices. The question type is Necessary Assumption, which means we need to identify the assumption the argument depends on.

a) More than one or two airplanes were scheduled for the nine canceled flights.

This is the correct answer. The argument assumes that more than one or two airplanes were involved in the nine canceled flights. If only one or two airplanes were scheduled for all nine flights, it would be possible for mechanical problems with those planes to cause all the cancellations. By assuming more than one or two airplanes were involved, the argument supports the conclusion that some cancellations were due to something else.

b) Swift Airlines has fewer mechanical problems than do other airlines of the same size.

This answer choice is not necessary for the argument. The argument is about the likelihood of mechanical problems with Swift's airplanes, not a comparison with other airlines.

c) Each of the canceled flights would have been longer than the average flight on Swift Airlines.

This answer choice is irrelevant to the argument. The length of the flights has no bearing on the cause of the cancellations.

d) Swift Airlines had never before canceled more than one or two scheduled flights on a single day.

This answer choice is not necessary for the argument. The argument is about the cause of the nine cancellations on a specific day, not about Swift's history of cancellations.

e) All of the airplanes scheduled for the canceled flights are based at the same airport.

This answer choice is also irrelevant to the argument. The location of the airplanes doesn't affect the cause of the cancellations.

In conclusion, the correct answer is A because the argument depends on the assumption that more than one or two airplanes were scheduled for the nine canceled flights.