CR - Weaken question!

lotrgandalf wrote:Can a correct option in critical reasoning, contain something that goes against the definition present in the premise? (refer OG 13 - CR question # 112)

Can you post the text of the question? (It's helpful for anyone else following the thread to be able to see what we're discussing.)

DavidG@VeritasPrep wrote:

lotrgandalf wrote:Can a correct option in critical reasoning, contain something that goes against the definition present in the premise? (refer OG 13 - CR question # 112)

Can you post the text of the question? (It's helpful for anyone else following the thread to be able to see what we're discussing.)

The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the free-wheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.

Which of the following, if true, most severely weakens the argument presented above?

(A) Cars, buses, and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.

(B) Cars and buses are not nearly as fast as the high-speed train will be.

(C) Planes are not a free-wheel system because they can fly only between airports, which are less convenient for consumers than the high-speed train's stations would be.

(D) The high-speed train line cannot use currently underutilized train stations in large cities.

(E) For long trips, most people prefer to fly rather than to take ground-level transportation.

lotrgandalf wrote:

DavidG@VeritasPrep wrote:

lotrgandalf wrote:Can a correct option in critical reasoning, contain something that goes against the definition present in the premise? (refer OG 13 - CR question # 112)

Can you post the text of the question? (It's helpful for anyone else following the thread to be able to see what we're discussing.)

The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the free-wheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.

Which of the following, if true, most severely weakens the argument presented above?

(A) Cars, buses, and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.

(B) Cars and buses are not nearly as fast as the high-speed train will be.

(C) Planes are not a free-wheel system because they can fly only between airports, which are less convenient for consumers than the high-speed train's stations would be.

(D) The high-speed train line cannot use currently underutilized train stations in large cities.

(E) For long trips, most people prefer to fly rather than to take ground-level transportation.

Two ways to see this. The first is that this is an incredibly rare instance of an exception to the rule that you can't undermine a premise: https://www.beatthegmat.com/the-difficul ... 85718.html

The second is to think of it this way. One premise is that a plane can fly anywhere. An intermediate conclusion based on this premise is that aircraft constitute a free-wheel system. The correct answer undermines this intermediate conclusion. (Of course, this way of thinking may be something of a stretch.)

In any event, I think it's useful to go into the test with the idea that we can't undermine the premises of the argument.