Because natural gas is composed mostly of methane, a simple hydrocarbo

Question

Because natural gas is composed mostly of methane, a simple hydrocarbon, vehicles powered by natural gas emit  less of certain pollutants than the burning of gasoline or diesel fuel .

(A) less of certain pollutants than the burning of gasoline or diesel fuel
(B) fewer of certain pollutants than burning gasoline or diesel fuel do
(C) less of certain pollutants than gasoline or diesel fuel
(D) fewer of certain pollutants than does burning gasoline or diesel fuel
(E) less of certain pollutants than those burning gasoline or diesel fuel

commdiver · Accepted Answer

E

A simple trick to remembering whether to use "less" or "fewer" is to remember the sentence "If you eat fewer fries, you need less ketchup." You can count the fries (one fry, two fries, three fries, etc.), so you use the word "fewer". You cannot count ketchup (you cannot say one ketchup or two ketchup), so you use "less". Because of this B and D are eliminated.

A is incorrect because the sentence is trying to say the vehicles burning one fuel emit less pollutants than other vehicles burning another fuel. A is comparing the vehicles to the general burning of fuel, which distorts the meaning.

C is similar to A. C compares the vehicles to the fuels themselves.

I hope that helps

GMATNinja · Answer

First, you're right, the juiciest decision point is between "less" and "fewer." As is usually the case, the choice comes down to context and meaning. If we're talking about the  number  of pollutants emitted, we'd use "fewer" as this would be countable. If we're talking about the  quantity  of pollutants, we'd use "less" as the quantity of a volume isn't really countable. (A good rule of thumb here is whether the item in question can be expressed as an integer value. We can count to 3. But it doesn't make sense to count to 3.7.) Much more on countable vs. non-countable modifiers in  this video .

Here it seems more logical to talk about the quantity of "certain pollutants." If one vehicle emitted four kinds of pollutants and another three kinds, it's not clear if we should care. It would really depend on  how much  was emitted. Also, if we were talking about the number of pollutants, it would be far simpler to just writer "fewer pollutants," as opposed to "fewer of certain pollutants." Because we'd prefer "less," to indicate a non-countable quantity, (B) and (D) are out.

Next, take another look at (A):

Now it sounds as though we're comparing the amount of pollutants emitted by vehicles powered by natural gas to the amount of pollutants emitted by the burning of gas or diesel  in general . That's an awfully wonky comparison. Shouldn't we be comparing emissions from vehicles running on natural gas to emissions from other types of  vehicles ? I'm tempted to get rid of (A), but first, I might see if a more logical comparison is available.

(C) gives us the following:

If anything, this one is worse. Now we're comparing emissions of vehicles powered by natural gas to gasoline or diesel fuel  themselves . Fuel, so far as I know, doesn't just spew out emissions on its own. You have to use or burn it. So (C) is illogical and out of contention.

And here's (E):

Now we're comparing vehicles powered by natural gas to those (vehicles) burning gasoline or diesel. The vehicle to vehicle comparison is more logical than the comparison we get in (A) between vehicles powered by natural gas and the general burning of gas and diesel. Because (E) uses "less" correctly and offers the most logical comparison, it's our winner.

It's mostly a question of whether we need the helping verb, "do" or "does" to clear up an ambiguity.

Consider an example:

Tim hates Pokemon more than his wife.

Here, for the sake of Tim's marriage, we really want a helping verb. The reason is that the sentence, as is, has two possible interpretations:

1) Tim hates Pokemon more than his wife hates Pokemon. 
2) Tim hates Pokemon more than he hates his wife. (That's a problem, both for Tim and for the GMAT.)

However, if we write, "Tim hates Pokemon more than his wife  does ," it's now clear that the first interpretation is the correct one.

But not every sentence has two reasonable interpretations. For example, "Tim runs faster than Ben," doesn't include the helping verb "does," but because there's only one coherent way to understand the sentence, it's fine as is.

(E) is more like the second scenario that has only one logical interpretation. In other words, no reasonable person would read "Vehicles powered by natural gas emit less of certain pollutants than those burning gasoline or diesel fuel," and think there was any chance that the sentence meant that vehicles powered by natural gas emit less of certain pollutants than they emit vehicles burning gasoline.

Because there's no ambiguity here, the helping verb isn't required. And there's no rule about whether "does" should come before the subject or after.

I hope that helps!

seofah · Answer

First of all, let's sort "less of certain pollutants" out. It should start with "less". fewer pollutants = fewer NUMBER of pollutants. NUMBER is countable less of certain pollutants = less QUANTITY of certain pollutants. QUANTITY is non-countable Therefore, in our case it should start with "less" So, B and D are out! According to my analysis, E has the least number of errors. Anyone disagree with me?

Is there anyone who thinks E does not have any error?

JenRugani · Answer

Hi there! Just wanted to provide a quick clarification on less vs. fewer as it relates to this question. The basic rule is that less is used for uncountable items and fewer is used for countable items (I had fewer chairs but less time).

This can get tricky when we talk about categories of items; for example, you would have less jewelry (a broad uncountable category) but fewer necklaces (specific, countable items). Similarly, you would have less salt, but fewer grains of salt.

That's sort of what we see going on in this question -- we're referring to an uncountable amount of pollutants that has been emitted, so we use less. Another similar example: I had fewer bottles of perfume than my friend, but less OF my Chanel perfume had been used. The preposition is important in creating the distinction!

Hope that helps

Narenn · Answer

Because natural gas is composed mostly of methane, a simple hydrocarbon, vehicles powered by natural gas emit  less of certain pollutants than the burning of gasoline or diesel fuel.

(A) less of certain pollutants than the burning of gasoline or diesel fuel
(B) fewer of certain pollutants than burning gasoline or diesel fuel do 
(C) less of certain pollutants than gasoline or diesel fuel
(D) fewer of certain pollutants than does burning gasoline or diesel fuel 
(E) less of certain pollutants than those burning gasoline or diesel fuel

I know choice B is wrong because of Incorrect usage of 'fewer', however i would like to know that when comparing the actions if the second part to be compared repeats the verb -  do  in this case - can  that  or  those  be understood in such case.
i.e. if the choice B had been  less of certain pollutants than (those) burning gasoline or diesel fuel do  would this choice be correct?

PrashantPonde · Answer

Your query: I know choice B is wrong because of Incorrect usage of 'fewer', however i would like to know that when comparing the actions if the second part to be compared repeats the verb - do in this case - can that or those be understood in such case.
i.e. if the choice B had been less of certain pollutants than (those) burning gasoline or diesel fuel do would this choice be correct?

Vehicles powered by natural gas emit less of certain pollutants than (those?) burning gasoline or diesel fuel do
-- "Those" is required in above comparison, otherwise it will appear that "vehicles" are being compared with "burning of fuel".

murilomoraes · Answer

I totally disagree with the OA, because we can not compare car powered by vs burning of, this question are comparing two different things.

BassanioGratiano · Answer

So the hint to figuring out whether to use less or fewer is the word "certain". There are certain pollutants.

There are certain kinds of cows.
There are certain classification of stars. 
There are certain amount of isotopes.

The word certain gives us a hint that we are dealing with a classification of pollutants that are countable.

Let me know if I'm wrong.

sayantanc2k · Answer

The comparison is between "vehicles powered by natural gas" and "those (vehicles) burning gasoline or diesel fuel". Hence option E is correct.

AR15J · Answer

Hi Verbal Expert,

Most of the time, I solve comparison questions wrong. Probably, there is a lack of understanding of this concept.
I find it difficult where omission of some words will make the sentence incorrect and where it will not. Please explain. Thanks

I read one post earlier with the below examples on Comparison 
more babies were born to women over the age of thirty than under the age of 30

more babies were born to women over the age of thirty than to women under 30

more babies were born to women over the age of thirty than were born to under 30
all above is the correct---  Above all is correct  or  All above is correct

most babies were born to women over the age of thirty than born under 30(incorrect)
most babies were born to women over the age of thirty than they were under 30(incorrect)

sayantanc2k · Answer

Omission is allowed only when the meaning is not obscured.

I like chocolates more than Karishma... ambiguous - 2 possible meanings are:
1. I like chocolates more than I like Karishma.
2. I like chocolates more than Karishma likes chocolates.

In such cases omission is not acceptable.

sayantanc2k · Answer

"Pollutants" is countable (plural form implies countable noun). Hence "fewer" is correct. Option B and D remains. "Burning gasoline or diesel fuel" is singular, hence the correct verb is singular "does". D remains.

OA has been added.

OA has been added.

mikemcgarry · Answer

At this MGMAT forum link , the great genius Ron Purewal verifies that the answer is (E). What's extremely tricky about the countable/uncountable structure in this question is the following. The sentence is NOT saying that the " vehicles powered by natural gas " emit fewer of the pollutants, a shorter overall list of different pollutants. Instead, the sentence is saying that, for each pollutant, these vehicles emit less of that pollutant, a smaller amount of that particular pollutant. We are not counting the number of pollutants, but instead talking about the amount of each pollutant. That's the tricky distinction in this question. Does all this make sense? Mike

sayantanc2k · Answer

Yes  mikemcgarry , I see the point. Thank you.

carcass  Thank you for changing the OA.

adityapareshshah · Answer

Hi Mike,
Thanks for the explanation. Can you however explain how did you conclude that the sentence is not talking about reduction in the number of pollutants but it is talking about the reduction in that the quantity of pollutants emitted.
Also how can the sentence be framed in case we want to refer to the number of pollutants?

Regards,
Aditya

mikemcgarry · Answer

Dear Aditya, I'm happy to respond. :-)

For me, the tipoff was the idiomatic word " of ." Using that word in the construction would be awkward if we were trying to talk about the number of pollutants. For the amount of each pollutant, we would say: 1) ... emit less of certain pollutants than those burning gasoline or diesel fuel . Natural gas has pollutants, many in common with the pollutants of gas or diesel, but natural gas releases less of at least some of those shared pollutants. The word " certain " is implied to be in reference to the shared pollutants they have in common. This is all quite sensible. For the number of pollutants, the easiest thing to say would be: 2) ... emit fewer pollutants than those burning gasoline or diesel fuel . That gets the meaning across, plain and simple. You see, it is not grammatically wrong or rhetorically awkward to say: 3) ... emit fewer of certain pollutants than those burning gasoline or diesel fuel This has a different meaning, a somewhat bizarre meaning. This implies that we have some fixed list of specific pollutants, a kind of "greatest hits" of pollutants. From this external list, we are checking off how many are released by gas or diesel, then how many are released by natural gas, and it turns out that natural gas emits fewer from this external list. What's bizarre about this scenario is that, unlike #1, the situation is no longer self-contained. There's an external list of pollutants, some fixed list, to which the fuels are being compared. All the comparisons in the sentence are ultimately hinged on a reference list that is never explicitly mentioned. There's a spooky shadowy background force having an influence on the sentence! The salient point is would be simply that natural gas emits fewer pollutants, and this idea is expressed very clearly in #2. We don't need all the extraneous ideas brought in by #3. Since all five answer choices have the word " of ," essentially I was choosing between the perfectly sensible and rational world of #1 and the strange spooky world of #3. That's why I thought #1 was better. Does all this make sense? Mike :-)

BijayKru · Answer

Because natural gas is composed mostly of methane, a simple hydrocarbon, vehicles powered by natural gas emit less of certain pollutants than the burning of gasoline or diesel fuel.

(A) less of certain pollutants than the burning of gasoline or diesel fuel
(B) fewer of certain pollutants than burning gasoline or diesel fuel do
(C) less of certain pollutants than gasoline or diesel fuel
(D) fewer of certain pollutants than does burning gasoline or diesel fuel
(E) less of certain pollutants than those burning gasoline or diesel fuel

LESS is perfect for that, fewer is wrong
E is the correct one

renzofig · Answer

Hi experts  GMATNinja ,  GMATNinjaTwo ,  daagh ,  TommyWallach ,

I think that this questions has a great less/fewer split. Maybe you could complement the explanations with your thoughts.

Also, could you explain why the correct answer Choice E does not use the "do" to replace the verb "emit".

Shouldn't the answer be as follows:

E) less of certain pollutants than those burning gasoline or diesel fuel  "do"

Also, is it appropiate to use "do" after the subject or "do" must be placed before the subject?

Best regards,
Renzo

Avysar · Answer

The sentence basically compares vehicles powered by natural gas and those using diesel/ fuel. Also it is talking about emission of certain pollutants, which is the quantity and hence uncountable.
A compares the vehicles with burning of fuel. Hence incorrect comparison
B and D use 'fewer' which is incorrect
C compares vehicles with the fuel. Incorrect
E compares vehicles using natural gas and vehicles that burn fuel. It also has the correct adjective'less' for the amount emitted.
Hence E is the answer

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Because natural gas is composed mostly of methane, a simple hydrocarbo

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GMAT Sentence Correction (SC - EA only) Questions

Because natural gas is composed mostly of methane, a simple hydrocarbo

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