Because the population is denser there and the auto mobile is therefor

This is a comparison question. D is correct.

Because the population is denser there and the auto mobile is therefore inefficient as a means of transportation, a commuter rail system serving a given population is usually five times more efficient in a European city than it is in an American city.


a serving a given population is usually five times more efficient in a European city than it is in an American city
Wrong. "it" refers to a commuter rail system in a European ==> Wrong because it compares to itself.

b serving a given population will usually be five times more efficient if it is placed in a European city instead of an American city
Wrong. Bad grammar. "more efficient if X instead of Y" sounds awkward.

c will usually be five times more efficient in a European city than one serving a comparable population in an American city
Wrong. The comparison is "more efficient in a European city than one" ==> "a European city" compares to "one"

d in a European city will usually be five times more efficient than will a system serving a comparable population in an American city
Correct. Structure is: X in a European city will usually be five times more efficient than will Y in an American city

e that is implemented in a European city will usually be five times more efficient than if it is implemented with a comparable population in an American city
Wrong. Like C, bad grammar: X in a European city will be five times more efficient than if X in American city

Hope it helps.

Dear CharlesBarclay & aditya8062,
I'm happy to respond. I am not sure that I like this question. It seems to play on subtleties a bit more than the GMAT does.

Part of what is awkward about the prompt and choice (B) is putting the "serving a given population" at the beginning, before the comparison. This tells us the hyper-obvious information that the commuter rail system serves a population (i.e., they tend not build these in the middle of the desert with nobody around!!), and illogically, it suggests that the phrase applies to both parts of the comparison, that the rail system would serve the same given population in both the European city and in the American city. That is 100% illogical and not what the author is trying to say. Choices (A) & (B) are wrong.

Choice (E) is an unholy abomination. It seems to be trying to win a contest for the longest and most awkward possible answer. This one should be taken out back and shot. Clearly wrong.

That leaves us with (C) & (D). Both are grammatically correct. Both are plausible. I believe the reason the question writer wants us to reject (C) is the placement of the word "there" before the underlined part. The "there", where it appears, leaves a question hanging --- exactly about what place are we speaking?? The urgency of that question demands that a clear and unambiguous answer come as soon as possible. Think about the way (C) begins ----
(C) will usually be five times more efficient in ....
So we go that whole distance without getting an answer to our question, and we don't get an answer until the comparison. Slightly awkward. Meanwhile,
(D) in a European city will usually ....
BAM! Right away, the answer to our question. This one doesn't leave us hanging nearly as long, so in some subtle sense, it's more "satisfying." Let me say, though: the difference (C) and (D) here is ridiculously subtle, and absolutely is not characteristic of a GMAT SC question. The GMAT has very high standards. On GMAT SC, one answer is unambiguously correct, and each of the other four answer choices has something absolutely definitive and objective that is wrong. It's very hard to write high quality SC practice questions that adhere to this standard. Poorly written questions sometimes will try to create splits based on bizarrely subtle details, and the authors no doubt believe that they have written a good challenging question, but this is absolutely not in the spirit of the GMAT, and, in fact, it betrays an astonishing lack of familiarity with the standards of the GMAT.

I don't like this question at all. Here's a much better question for practice:
https://gmat.magoosh.com/questions/3604

Let me know if you have any further questions.

Mike
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option A:a commuter rail system serving a given population is usually five times more efficient in a European city than it is in an American city.
i somehow find this comparison faulty (both grammar and logic) .had A been like this :a commuter rail system serving a given population is usually five times more efficient in a European city than in an American city. then the comparison would have been oki grammatically though i still feel that the intended meaning is missing in the modified version .

Hey Mike,

I quite did not get the difference between options c & d, especially the place of "there" part. Would you explain it again ?

Thanks !

Dear vishalrastogi,
I'm happy to help. Here's the entire problem again:

Because the population is denser there and the automobile is therefore inefficient as a means of transportation, a commuter rail system serving a given population is usually five times more efficient in a European city than it is in an American city.
(A) serving a given population is usually five times more efficient in a European city than it is in an American city
(B) serving a given population will usually be five times more efficient if it is placed in a European city instead of an American city
(C) will usually be five times more efficient in a European city than one serving a comparable population in an American city
(D) in a European city will usually be five times more efficient than will a system serving a comparable population in an American city
(E) that is implemented in a European city will usually be five times more efficient than if it is implemented with a comparable population in an American city

Think about just the beginning of the sentence:
Because the population is denser there and ...
If that's all we heard of the sentence, we would have absolutely no clue where on earth the population was denser. We would have absolutely no clue as to the physical location about which the speaker is speaking. The writer or speaker has a specific geographic location in mind, and is telling us important things about that location, but at least at the outset, we are 100% in the dark about where on Earth the writer or speaker might mean.

Ordinarily, ambiguity in sentences is bad. The GMAT loves sentence that are crisp and clear and direct, sentence that efficiently communicate everything they are trying to say. In general, anything unclear or unspecified is a bad thing. Here, though, is a kind of exception. Sometimes, for rhetorical effect, it can be good thing to specify something or someone, the identity of which the reader doesn't know right away. The writer, by using this word "there" at the beginning of the sentence, has piqued our curiosity. This creates a kind of tension that generates forward momentum through the sentence --- we read the "there" and we are curious: we want to know the place about which the writer is talking, and this impels us to continue reading the sentence. This is one subtle trick for producing engaging writing.

Imagine if I began a sentence
"Because she was one of the most intelligent women ever to live, ..."
that sentence beginning would create enormous expectations. Wow! the reader would feel, we are going to find out at least one person's opinion on who the smartest woman of all time was. There's a very clear expectation that immediately following that opening phrase will be the name of this very impressive woman. Creating expectations in a sentence is a good thing if we fulfill those expectations. It becomes awkward if I create expectations, and then don't satisfy them:
"Because she was one of the most intelligent women ever to live, the university system at the turn of the century, after the Greek requirement had been dropped ...."
WAIT A MINUTE! That sentence cheated us. It created the expectation that we were going to find out the name of this very impressive woman, and then after the comma, it started talking about something else. Yes, the woman probably will be mentioned at some point, but because this mention is delayed, it frustrates the expectation.

BTW, I'm sorry, but I have no idea whom I would name as the smartest woman of all times.

This sentence creates a similar tension with the word "there", and version (D) immediate resolves the tension by letting us know right away that "there" means "in a European city." Choice (D) creates tension, creates an expectation, and then promptly resolves it.

By contrast, choice (C) create the same expectation, but then leaves us hanging longer. It's a little more ambiguous in (C) exactly which location is the one the author was suggesting in the first half of the sentence. This is somewhat analogous to my red sentence above --- the sentence creates a clear expectation, and then it is not so efficient about satisfying this expectation. That's a somewhat awkward move.

As I said above, the GMAT SC absolutely DO NOT test subtleties of this magnitude. The GMAT does not do a whole lot of this "building rhetorical tension" in sentence. The GMAT is much more straightforward and factual.

Does all this make sense?
Mike
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I take the opportunity of stating my bit , daring to do so , however undoubtedly the OE and the best reply will surely be provided by souvik101990

Here the meaning of the sentence is clear it Compares -


In (D) we are comparing-

The commuter rail system in a European city with the commuter rail system in an American city

Further the choice (D) has the following issues -

1. Parallelism : in a European city ............. in an American city

2. Comparison : more .........than.........

So IMHO (D), souvik101990 awaiting your Official explanation...
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this question tests parallelism and comparisons. 'than' is a parallel marker.

A - the problem is with the word 'it'. It/they/them/their refer to the same copy, whereas those/that refer to a different copy. Another thing to remember is 'it' refers to the noun with all its modifiers. This option thus absurdly implies that the same commuter system is more efficient when it is used in Europe.
B - Let us rewrite this option - if the commuter system is placed in a European city instead of an American city, the commuter rail system will usually be five times more efficient. this is absurd. We cannot transfer the commuter system across continents.
C - This option compares "a commuter rail system" with "commuter rail system serving a comparable population in an American city" - Not parallel. We need to compare the commuter rail system in Europe to commuter rail system in US. Also, "a commuter rail system will usually be five times more efficient in a European city" implies that if we transfer a commuter system to Europe, it becomes more efficient.
D - correct answer. correct comparison between - 'a commuter rail system in a European city' and 'a system serving a comparable population in an American city'.
E - 'it' has the same problem as mentioned in A. 'if it is implemented ...' is also not parallel.
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Is my thought process correct if I just look for the answer choice that has a "In a European City" closest to the start of the answer choice. I am doing so because the first part of the sentence is a modifier(?) that is modifying "A European City". So the answer choice has to be the one with the European City closest to the beginning.

This was just my 2 cents...

Also (as you can tell) I'm new to the forum. Are the verbal and math questions of the day - devised from GMAT Club Forum users, so anyone can create a question of the day? If not, who/where are the questions and answers coming from?

I'm noticing a surprising trend that a lot of the Quant questions test inane/slightly obscure concepts, but the Verbal questions are slightly more reasonable, yet still have a rough edge to them...

(could just be me tho)

The first part is not a modifier, but a dependent clause starting with "because". Hence the position of "in European city" is not critical to answer this question.

Your other queries about the questions of the day will be replied to shortly.

I don't want to imply anything but the quant questions are tricky questions from the GMAT Club tests. They are designed to test your knowledge, not make you feel comfy. These are 700+ level questions, so they tend to be unusual - often something you have not encountered before and something that requires you to think out of the box.
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As per my opinion....

Because the population is denser there and the auto mobile is therefore inefficient as a means of transportation, a commuter rail system serving a given population is usually five times more efficient in a European city than it is in an American city.

a serving a given population is usually five times more efficient in a European city than it is in an American city : no clear antecedent of "it"

b serving a given population will usually be five times more efficient if it is placed in a European city instead of an American city: idiom error.

c will usually be five times more efficient in a European city than one serving a comparable population in an American city: "one" is ambiguous.

d in a European city will usually be five times more efficient than will a system serving a comparable population in an American city : correct comparison

e that is implemented in a European city will usually be five times more efficient than if it is implemented with a comparable population in an American city : no clear antecedent of "it"

Hi,

D straight way wins because rest choices talk as if it is the same commuter rail system that is placed at both places..

But we are comparing the system in place A with system in place B..

Now about future tense..
There is nothing wrong here. You are talking of effect of some activities if done in future.
Example- he will win the game because he is a better player.
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Hi chetan2u and all,
I am confuse with the additional word "comparable" in the correct choice. Does this change the meaning?
Also,I don't see anything wrong to compare the existing rail systems in option A.

In my 2 cents,option A says that the current population in EC is denser than in AC;hence the rail system in EC is more efficient than that in AC.
On the other hand,option D says that the current population in EC is denser than in AC;hence the rail system in EC will usually be more efficient than that serving a comparable population in AC.

Hi,

A uses 'given population' so here given works the same way as comparable....
Otherwise it would be just 'its population'.

Example :- in the given scenario, country x will emerge stronger than country y..

But A has a problem in comparison of commuter rail system.
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As I struggle to really understand why: could you give a short POE explanation for this?

In my opinion, options C and D both are gramatically alright. C may be considered better because of concision.

Option A may be considered wrong because it appears that the same rail system serves both a European city and an American City (because of the usage of pronoun "it").
Option B is wrong also because of the same reason as above. Moreover there is no "than" corresponding to the comparative adjective "more".
Option E is wrong because of the same problem as described for A.

A and B seem to suggest that the commuter rail system would serve the same populations in both American and European cities, that is not possible and not what the sentence is supposed to mean. These two are out.

E is just ridiculously wordy. There is very little chance that this is the right one. I am only going to consider it if both of the remaining two are very flawed.



C and D are actually both correct, logically and grammatically. Its hard to tell which is better. D is I think slightly better sounding, so I will pick D.



Curious to see what others picked.

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