There is only one major road, Freeway Z, that links County X

[JbhB682]

Source : Manhattan

There is only one major road, Freeway Z, that links County X and County Y. The border of the two counties is primarily defined by a mountain range, over which the construction of new roads is severely restricted by environmental laws. A cost-effective solution to the problem of traffic congestion on Freeway Z is to build a commuter train tunnel through the mountain range. The successful implementation of this plan would cost far less than expanding the existing freeway and would also reduce the number of cars clogging the roads in both counties.

Which of the following, if true, could proponents of the plan above most appropriately cite as a piece of evidence for the soundness of their plan?

A. An effective commuter train tunnel between the counties would require major investment in mass transit within both counties.
B. The majority of all vehicles on the nation’s freeways are traveling from one state to another.
C. 60% of the cars on Freeway Z are driven by people who live in County Y and work in County X.
D. Many new freeways are being built in areas that are presently served by commuter trains.
E. A large proportion of the vehicles on Freeway Z are commercial trucks carrying transcontinental shipments

OA : C

[JbhB682]

This I believe is a "PLAN" argument and one is looking for an answer that could be used as further evidence for the soundness of the plan-- in other words, a new premise that will SUPPORT/STRENGTHEN the conclusion that successful implementation of the plan will (1) cost less than freeway expansion and (2) reduce congestion in both counties.

I don't see how option C **strengthens** whether the successful implementation of the commuter train will (2) reduce congestion in both counties.

Unless you are first sure if the 60 % of commuters (Driving on free way z daily to get to work) will first EVEN SHIFT to the commuter train first.

I don't see any evidence for a shift in option C

Q1) Are we not skipping a step (if the commuters will even SHIFT from cars to trains) when we choose C ?

Q2) Would you agree a more DIRECT strengthener to the Plan would give evidence to suggest commuters on freeway Z would first SHIFT to the planned train, thereby (2) reducing congestion in both counties.

Q3) If evidence of a SHIFT from commuting to train was given -- would that would be TOO easy ? Given this is tougher question, we are being asked for skip a step ?

[esledge]

On Strengthen questions, you only need an answer that makes the conclusion slightly more likely to occur or be true.

This conclusion includes a provision for successful implementation: “the successful implementation of this plan would … reduce the number of cars clogging the roads in both counties.”

Thus, (C) suggests that a majority of the cars on Freeway Z could be removed if the commuter train tunnel is built, tying the existence of the train to the possibility of removing cars from the roads.

Q1) It is not necessary to know that commuters WILL shift from cars to trains; it is enough to know that they COULD and that if they do, it will unclog the roads.
Q2) Yes, I agree that would make for a stronger strengthener.
Q3) Yes, it would probably be easier with that connection emphasized. (To measure the difficulty of a question, we’d collect and analyze actual student answers to the question—this is how GMAC and also MPrep measures question difficulty.)

The more salient point is that you will never be asked to choose between (C) as written and (C) with your suggested variation. Even though the wording of Strengthen questions is often “which of the following, if true, would most strengthen?” (emphasis mine), the “most” does not suggest that the GMAT will give you several strengthening choices that you will then need to rank by strengthening factor. In practice, only one answer choice will actually Strengthen the conclusion, and the other four will either be opposite (weakening) or irrelevant.

[JbhB682]

Q1) It is not necessary to know that commuters WILL shift from cars to trains; it is enough to know that they COULD and that if they do, it will unclog the roads.
.

Hi Emily - Thank you for your response

The above statement seems to be opening the possibility of "speculation games" or what is call "hopeful assumptions"

I have made errors on OTHER problems making these "hopeful assumptions"

It "Could" be possible / It "may" be possible / Couldn't that mean x, y or z ....

Below, after reading this post on other problem - my takeaway was not make any hopeful assumptions with answer choices

https://www.manhattanprep.com/gmat/foru ... ml#p144006

[esledge]

The difference is in how much "hopeful assuming" you have to do. If you have to assume a chain of events/causality to link a choice to an effect on the conclusion, you are doing too much. If you are just thinking of the logical consequence of the choice and it is already closely tied to the argument/conclusion, that's ok.

On (C) in this Freeway Z question, the only "assuming" necessary is explicitly allowed by the questions stem ("Which of the following, if true, ..."). You are told to accept the fact that 60% (a majority) of the cars on Freeway Z are driven by the very same commuters mentioned in the argument.

Also note the light wording of the rest of the question stem: "Which of the following ... could proponents of the plan ... cite as ... evidence for the soundness of their plan?" Paraphrased, that's like asking "which of the following MIGHT make proponents of the plan think that the plan above MIGHT work as hoped?" That's far less demanding than "What PROVES that the plan is sound?" and I think you are going wrong by trying to meet the latter standard.