Dirt roads may evoke the bucolic simplicity of another century, but fi

Dirt roads may evoke the bucolic simplicity of another century, but financially strained townships point out that dirt roads cost twice as much as maintaining paved roads.

(C) maintaining dirt roads costs twice as much as paved roads do.
In this option if we change do to does then whether this will be correct?

Hi GAURAV1113, that will make option C worse than it already is! Since paved roads is plural, we need a plural verb do and not a singular verb does.

I understand paved roads is Plural but as per my understanding maintaining paved roads will need singular verb does, My question was why we cannot extend "maintaining" to paved roads, It is allowed as per ellipsis.?

Ok I understand your point Gaurav. So, if the verb is do, it is obviously clear that paved roads is the subject, while if the verb is does, then we interpret that since paved roads is plural, we need to imply that the word maintaining is elided, so that the verb matches with maintaining.

While it might be a tough ask to codify the exact rules here, in comparison questions, it often comes down to choosing the best of the available options; in B, since do very clear stands for cost to maintain, I would still prefer B.

This is all about being supremely literal with comparisons, as we'll discuss in this week’s YouTube webinar. And I don't think that anybody really loves comparisons, so… I dunno, try to enjoy this one anyway.

This is literally saying that dirt roads themselves cost more than maintaining paved roads. That doesn’t work: we either need to compare “maintaining dirt roads” to “maintaining paved roads” or we can compare the two types of roads. But (A) makes no sense in its current form.

This sounds pretty good! The key here is that the word “do” can replace a verb phrase – and in this case, “do” replaces “cost… to maintain.” So this is saying that “dirt roads cost twice as much to maintain as paved roads [cost to maintain].” Great, that makes sense. Let’s keep (B).
Here, "do" can also refer to "cost" and not "cost to maintain", right? And, in case it refers only to "cost", the sentence is no longer logically parallel as:
"dirt roads cost twice as much to maintain as paved roads COST". This could mean:
i). dirt roads cost twice to maintain VS the cost of main roads - illogical comparison, right?
ii). dirt roads cost twice to maintain VS paved roads cost [to maintain] - Here, can we consider that "to maintain" is omitted? If yes, how do we decide if it's omitted?
How do we conclude that it refers to "cost to maintain", and not just to "cost".


This is lamentably subtle. Keep in mind that “do” replaces a verb phrase – and “maintaining” is a noun (gerund) in this case, and definitely not a verb. (For more on –ing words, check out this article: https://gmatclub.com/forum/experts-topi ... 39780.html.) So this is literally saying that “maintaining dirt roads costs twice as much as paved roads [cost].” Now we’re comparing the cost of maintaining dirt roads with the cost of paved roads themselves, and that doesn’t makes sense.

Tricky, but definitely wrong. (C) is gone.

The “it” jumps out at me here. If we’re being charitable, I suppose we could accept the idea that “it” refers back to “maintaining”, since “maintaining” is a noun. So we have “maintaining dirt roads costs twice as much as [maintaining] does for paved roads.” Really? I guess that’s not totally illogical, but it’s a muddy mess, and it’s a whole lot less clear than (B). So (D) is out, since (B) is undoubtedly clearer.

I don’t see any reason why we would use the infinitive “to maintain” as a noun here. That’s not something that you’ll see very often in correct answers on the GMAT. I’m not 100% certain that it’s absolutely wrong, but it’s definitely inferior to (B).

Just as importantly, if we’re going to use the infinitive “to maintain” as the subject of the clause, then it’s only going to makes sense if the comparison is parallel. Something like “to maintain dirt roads costs twice as much as to maintain paved roads” would at least be parallel. (E) in its current form doesn’t make any sense, since “to maintain dirt roads” is compared with just the prepositional phrase “for paved roads.”

So (B) is our winner.

Thank you GMATNinja for the nice explanation. I have a silly question- how do we conclude that "do" in option B refers to which verb/verb phrase? I have detailed below in red.
Request experts to please correct if I am missing something here.

Not a silly question at all! Whenever you see a helping verb, such as "do," the most logical place to look for the verb it stands for is the first clause in the comparison. Take a simple example:

Tim eats as much peanut butter out of the feeder as the birds do.

In this case, you can just let your eyes drift backward from "do" until you encounter the verb in the initial clause, "eats." Tim eats as much peanut butter as the birds eat. Pretty straightforward.

However, if the sentence is a little more complicated, and there's a longer verb phrase, it's often fair to assume that the helping verb stands in for that entire phrase. For example:

Tim wants to eat as much peanut butter as the birds do.

Now, "do" seems to stand in for the full verb phrase, "wants to eat." Tim wants to eat as much peanut butter as the birds want to eat. But even if you missed the infinitive ("to eat") when thinking about what "do" stands in for, you'd be left with the notion that Tim wants to eat as much peanut butter as the birds want. That still seems fine to me. At the very least, it certainly wouldn't be grounds for eliminating an option.

Same deal here. Whether you interpret (B) to mean "dirt roads cost twice as much to maintain as paved roads cost to maintain," or "dirt roads cost twice as much to maintain as paved roads cost," the comparison seems logical enough to hang on to the option.

The takeaway: when you see a helping verb such as "do," don't stress about whether it stands in for a lone verb or a full verb phrase. Simply go back to the main verb of the preceding clause. If there's a reasonable way to interpret the "do," move on to other decision points.

I hope that clears things up a bit!

Thank you GMATNinja. I get your point. However, isn't there a slight difference between the infinitive in Option B and the infinite in your example? Sharing my 2 cents below:

Tim wants to eat as much peanut butter out of the feeder as the birds do.
Here, even if "do" represents only "want". We can ask, what birds want? Answer: to eat. So, "want to eat" is obvious in this example.

However, in option B,
dirt roads cost twice as much to maintain as paved roads do.
"do" is conveying completely different comparisons when considered without "to maintain".

Case 1 (without "to maintain"): dirt roads cost twice as much to maintain as paved roads cost.
This implies, the cost of maintenance of dirt road is compared with the cost of paved road. [Isn't this the WRONG comparison?]

Case 2 (with "to maintain"): dirt roads cost twice as much to maintain as paved roads cost to maintain.
This implies, cost of maintenance of dirt road is compared with the cost of maintenance of paved roads. [Comparison seems perfect.]

Dirt roads may evoke the bucolic simplicity of another century, but financially strained townships point out that dirt roads cost twice as much as maintaining paved roads.


(A) dirt roads cost twice as much as maintaining paved roads

(B) dirt roads cost twice as much to maintain as paved roads do

(C) maintaining dirt roads costs twice as much as paved roads do

(D) maintaining dirt roads costs twice as much as it does for paved roads

(E) to maintain dirt roads costs twice as much as for paved roads

Hi! In this question I understood all the comparison issues in deep. But I got bugged by the fact that there might be a subject verb agreement issue in E which nobody talked about. "to maintain dirts roads COSTS". is there a subject verb error or not? AndrewN IanStewart

Dirt roads may evoke the bucolic simplicity of another century, but financially strained townships point out that dirt roads cost twice as much as maintaining paved roads.

maintaining dirt roads costs twice as much as paved roads do

This is all about being supremely literal with comparisons, as we'll discuss in this week’s YouTube webinar. And I don't think that anybody really loves comparisons, so… I dunno, try to enjoy this one anyway.

This is literally saying that dirt roads themselves cost more than maintaining paved roads. That doesn’t work: we either need to compare “maintaining dirt roads” to “maintaining paved roads” or we can compare the two types of roads. But (A) makes no sense in its current form.

This sounds pretty good! The key here is that the word “do” can replace a verb phrase – and in this case, “do” replaces “cost… to maintain.” So this is saying that “dirt roads cost twice as much to maintain as paved roads [cost to maintain].” Great, that makes sense. Let’s keep (B).

This is lamentably subtle. Keep in mind that “do” replaces a verb phrase – and “maintaining” is a noun (gerund) in this case, and definitely not a verb. (For more on –ing words, check out this article: https://gmatclub.com/forum/experts-topi ... 39780.html.) So this is literally saying that “maintaining dirt roads costs twice as much as paved roads [cost].” Now we’re comparing the cost of maintaining dirt roads with the cost of paved roads themselves, and that doesn’t makes sense.

Tricky, but definitely wrong. (C) is gone.

The “it” jumps out at me here. If we’re being charitable, I suppose we could accept the idea that “it” refers back to “maintaining”, since “maintaining” is a noun. So we have “maintaining dirt roads costs twice as much as [maintaining] does for paved roads.” Really? I guess that’s not totally illogical, but it’s a muddy mess, and it’s a whole lot less clear than (B). So (D) is out, since (B) is undoubtedly clearer.

I don’t see any reason why we would use the infinitive “to maintain” as a noun here. That’s not something that you’ll see very often in correct answers on the GMAT. I’m not 100% certain that it’s absolutely wrong, but it’s definitely inferior to (B).

Just as importantly, if we’re going to use the infinitive “to maintain” as the subject of the clause, then it’s only going to makes sense if the comparison is parallel. Something like “to maintain dirt roads costs twice as much as to maintain paved roads” would at least be parallel. (E) in its current form doesn’t make any sense, since “to maintain dirt roads” is compared with just the prepositional phrase “for paved roads.”

So (B) is our winner.

Hi,

Apart from the elusive comparison error that is the bread and butter of this GMAT SC Question. Notice something interesting.

(C) maintaining dirt roads costs twice as much as paved roads do

(D) maintaining dirt roads costs twice as much as it does for paved roads

(E) to maintain dirt roads costs twice as much as for paved roads

It's maintaining [adjective] dirt roads [subject of that clause] costs [verb] of the subject.
But, the subject = plural and the verb costs = singular.

We can eliminated C, D, E basis this. Any thoughts?