LSAT Explanation PT 26, S2, Q11: Commercial passenger airplanes can be equipped

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 A. 

LSAT Question Complete Explanation

First, let's analyze the argument in the passage. The author claims that passengers are safer on airplanes equipped with a collision-avoidance radar system than on comparable airplanes without the system. The premises are as follows:

1. Commercial passenger airplanes can be equipped with a collision-avoidance radar system.

2. The system provides pilots with information about the proximity of other airplanes.

3. The system warns pilots to take evasive action when it indicates a possible collision.

4. The system frequently warns pilots to evade phantom airplanes.

The conclusion is that passengers are safer on airplanes equipped with the system than on comparable airplanes without the system.

Now, let's think of an "Evaluate" question for this argument: "Does the evasive action taken in response to the system's warnings pose any risk to passengers?"

The question type of this problem is Strengthen, and we are asked to identify the answer choice that most strengthens the argument.

a) Evasive action taken in response to the system's warnings poses no risk to the passengers.

This answer choice directly addresses our "Evaluate" question and eliminates the concern that evasive action could pose a risk to passengers. If the evasive action doesn't pose any risk, then the system indeed makes passengers safer, even when it warns pilots to evade phantom airplanes. This strengthens the argument, making it the correct answer.

b) Commercial passenger airplanes are in greater danger of colliding with other airplanes while on the ground than they are while in flight.

This answer choice doesn't strengthen the argument, as it doesn't address the safety of passengers on airplanes equipped with the system compared to those without it. It only provides information about the relative danger of collisions on the ground versus in flight.

c) Commercial passenger airplanes are rarely involved in collisions while in flight.

While this information tells us that collisions in the air are rare, it doesn't help us determine whether the radar system makes passengers safer on airplanes with the system compared to those without it. It doesn't strengthen the argument.

d) A study by ground-based air traffic controllers found that 63 percent of the warnings by the system were invalid.

This answer choice could potentially weaken the argument, as it suggests that the system frequently gives false warnings. It doesn't help us determine whether passengers are safer on airplanes with the system compared to those without it.

e) The collision-avoidance radar system is run by a computerized device on the plane that scans the sky and calculates the distances between planes.

This answer choice provides information about how the system works but doesn't address whether passengers are safer on airplanes with the system compared to those without it. It doesn't strengthen the argument.

In conclusion, the correct answer is (A), as it directly addresses the "Evaluate" question and strengthens the argument by eliminating the concern that evasive action could pose a risk to passengers.