Many industrialized nations are trying to reduce atmospheric concentra

Conclusion : Therefore, using eco-cement for new concrete building projects will significantly help reduce atmospheric concentrations of carbon dioxide.
Pre -Think - What if even after absorbing carbon dioxide initially,eco cement would release its co2 after some time may be because of deterioration.Therefore in order to support the claim that eco cement will significantly reduce atmospheric concentrations of CO2, we have to show that this eco system will overall help in doing so.

Looking at option B:Eco-cement is strengthened when absorbed carbon dioxide reacts with the cement.
It does say that eco cement is a good cement but no-where it supports the conclusion that it will help decreasing concentration of Co2

Whereas option D : The manufacture of eco-cement uses considerably less fossil fuel per unit of cement than the manufacture of conventional cement does.
it actually provides additional information which supports the fact that usage eco-cement help in reducing overall CO2 content of the atmosphere.

I was also trapped in B for quite some time and could not get the point: Since the reaction between the new cement and the absorbed carbon dioxide could strengthen the cement, which could logically help the cement to absorb more carbon dioxide.
However,when I went back to context, I realized that the premise only told us the eco-cement absorbs a large amount of CO2, but it did not tell us the eco-cement absorbs LARGER amount than conventional one. So it is possible that even the strengthened cement absorbs less CO2 than conventional one. Then it can not strengthen the argument.

It is really an alluring trap.

this is a common pattern in gmat, test takers should learn this. That is, something must use less of something.

B has nothing to do with amount of carbon dioxide and green environment.

don't you think, we need to make sure that the cement is strong enough to be used for building?
Option B ) Support this the cement gets strengthen by aborbingCarbon dioxide.
Say, it if weakens by absorbing Carbon dioxide then it cant be used for building as it would be dangerous.

Moreover Option D) Even if Magnesium cement takes slightly more fossil fuel , but if it absorbs the Carbon dioxide efficiently, It will be helpful in reducing the Carbon dioxide.

please explain

Hello Dear gmatbusters,

Though I am not an expert or a moderator, I think I can help you in here.
IMO, you are mistaken for the main purpose here. We don't need to make sure that the cement is strong enough for the usage in the building, but all we need to make sure is there is less Carbon Dioxide omission in the atmosphere and that is correctly written in option D - the eco-cement uses considerably less fossil fuels as compared to the normal cement and thus less omission of carbon dioxide when the fossil fuels burn.

Surely, the eco cement is strengthened when it absorbs CO2, but it's strengthening is of less importance here and moreover, it is irrelevant as a strengthener.

I hope this helps.

Hi GMATNinja
How does burning of fossil fuel and using fossil fuels becomes equal, one can simply use fossil as an additive to the cement, isnt it? Premise covers that burning of fossil fuel releases CO2. I chose d ,however, the correct answer choice is skeptical.

So we know what argument we're dealing with in this question, let's take a look at the passage before examining your question:

• Governments are trying to reduce carbon dioxide emissions
• Carbon dioxide is a gas created by burning fossil fuels
• One proposal is to change one component in the manufacture of cement
• The new cement will absorb large amounts of carbon dioxide when it is exposed to the atmosphere
• Using this new cement will significantly help reduce the carbon dioxide concentration in the atmosphere

The passage is arguing that using the new "eco-cement" would help reduce carbon dioxide concentrations in the environment by absorbing carbon dioxide when it is exposed to the atmosphere. We're asked to find the answer choice that most strengthens this argument.

(D) tells us:

The passage tells us that carbon dioxide is "a gas released by the burning of fossil fuels." (D) tells us the manufacture of eco-cement "uses considerably less fossil fuel..." This does not mean the manufacturer adds fossil fuels into the cement as an ingredient, just that fossil fuels are burnt in the manufacturing of cement and manufacturing eco-cement means burning less fossil fuel than manufacturing conventional cement.

To say this, we DO need to make a minor leap to equate burning fossil fuels (from the passage) with using fossil fuels (from (D)). This might introduce a LITTLE doubt in (D) but let's take a wider look at the answer choice to see how it answers this question.

We already know that the eco-cement absorbs carbon dioxide when it is exposed to the atmosphere but (D) talks about the manufacturing of the eco-cement.

If conventional cement was replaced with eco-cement in any new building project, the amount of fossil fuel used to manufacture the cement would be lower. This tells us there would be less carbon dioxide released in the manufacturing of the eco-cement AND the eco-cement would absorb large amounts of carbon dioxide when exposed to the atmosphere.

(D) provides a second method for how the eco-cement would help reduce the concentrations of carbon dioxide in the atmosphere. Even with the little bit of doubt introduced by equating burning fossil fuels with using fossil fuels, as we talked about above, (D) strengthens the argument.

Since none of the answer choices strengthen the argument at all, (D) strengthens the argument MOST out of the available options -- this makes (D) the answer to this question.

I hope that helps!

GMATNinja AjiteshArun MartyTargetTestPrep

(D) says that manufacture of ecocement uses less fossil fuels per unit than that does normal cement.

But we don't know the number of units of cement manufactured in both cases. The amount of fossil fuels may still be the same. How does it act as a strengthener?

Hi Argp,

Let's take a look at the following statements:
1. One proposal is to replace conventional cement... by a new “eco-cement.”
2. This new cement... absorbs large amounts of carbon dioxide when exposed to the atmosphere.

Now, we don't know exactly how many units of eco-cement are required. The question doesn't seem to say anything about that, and test takers can't be expected to know anything about this, so we don't assume anything about the quantity/number of units.

Next, let's take a look at what the question wants:
3. Using eco-cement for new concrete building projects = significantly reduce atmospheric concentrations of carbon dioxide

We already know that eco-cement absorbs large amounts of carbon dioxide (let's call that "mechanism 1"). So that's one way replacing normal cement with eco-cement will help reduce atmospheric concentrations of carbon dioxide. Option D introduces a whole new "mechanism". It tells us that there is another way that switching to eco-cement will help: the manufacture of eco-cement uses considerably less fossil fuel. We can think of this as "mechanism 2". Effectively, D gives us two "mechanisms" targeting our objective ("significantly reduce atmospheric concentrations of carbon dioxide"), and that's why it is the best option in this set of five.

GMATNinja I know often times we see the test-takers quickly dismiss a choice because it is 'out-of-scope' ...to me that seems like a cop out (unless it is absolutely clear without a shadow of a doubt, that the choice is in fact irrelevant). Can you elaborate on this thinking?

For example, in this problem a lot of users ruled out a. However, one could argue that cost does play a role here. Suppose that the cost actually increases because of the higher demand...that would disincentivize builders who might then decide to search out cheaper alternatives...Hence if less people are buying the cement, then the idea that atmospheric CO2 will decrease is damaged.

Many industrialized nations are trying to reduce atmospheric concentrations of carbon dioxide, a gas released by the burning of fossil fuels. One proposal is to replace conventional cement, which is made with calcium carbonate, by a new “eco-cement.” This new cement, made with magnesium carbonate, absorbs large amount of carbon dioxide when exposed to the atmosphere. Therefore, using eco-cement for new concrete building projects will significantly help reduce atmospheric concentrations of carbon dioxide.

P: Industrialized nations are trying to reduce carbon dioxide concentrations
P: A proposal is to replace conventional cement with a eco-cement
P: Eco-cement absorbs large amounts of CO2 when exposed to the atmosphere
C: Eco-cement for new concrete building projects will significantly reduce atmospheric CO2

Which of the following, if true, most strengthens the argument?

(A) The cost of magnesium carbonate, currently greater than the cost of calcium carbonate, probably will fall as more magnesium carbonate is used in cement manufacture.
-cost is irrelevant

(B) Eco-cement is strengthened when absorbed carbon dioxide reacts with the cement.
-unnecessary detail that does not affect the conclusion at all

(C) Before the development of eco-cement, magnesium-based cement was considered too susceptible to water erosion to be of practical use.
-irrelevant detail; we aren’t interested in something that came before eco-cement, but whether eco-cement will reduce carbon dioxide in the future
-one might think that since eco-cement represents an improvement over magnesium-based cement that it will reduce CO2…while that’s possible…be wary of trying to make a story fit…

(D) The manufacture of eco-cement uses considerably less fossil fuel per unit of cement than the manufacture of conventional cement does.

You're right that it is generally good to find a stronger reason to eliminate an answer choice than just that it seems "out of scope." Sometimes it is hard to see a connection between the answer choice and the passage, but just because you don't SEE the connection immediately doesn't mean that there ISN'T a connection at all.

That being said, it is absolutely possible for an answer choice to have no impact on the strength of the author's argument.

In this passage, for example, the author concludes that "using eco-cement for new concrete building projects will significantly help reduce atmospheric concentrations of carbon dioxide." Cost really doesn't play a role at all in this conclusion. Even if eco-cement costs a million dollars per slab (or whatever the unit is for cement), using that cement would still reduce CO2.

So, while the information in (A) would potentially make it easier to afford eco-cement, that has no bearing at all on the argument. The author doesn't say that people actually will use eco-cement -- he/she just concludes that in a world where people DO use eco-cement, CO2 will be reduced.

You can eliminate (A) for that reason.

I hope that helps!

I understand why Choice D is the best answer. However, for Choice E, the Official Guide says this is incorrect because if anything the lack of awareness around eco-cement makes it less likely that it will be used to help reduce CO2 in the atmosphere.

On the flipside, can't you argue that the lack of awareness would be an opportunity set for use (unpenetrated market) = greater potential for a reduction in CO2? Or am I making too many assumptions here in that there would need to be:
-marketing to reach these buyers
-these buyers would have to WANT to reduce CO2
-these buyers would be willing to use this new product
-etc.?

I often tell my students about what I call the Three Key Questions for arguments in CR: https://www.youtube.com/watch?v=PfTcOr6zJjs

The three key questions are:

1). What would it mean for the conclusion to be false.
2). How could that happen, given that the premises are true?
3). What assumptions, then, must be true to save the argument?

This situation here is a good example of why that first one is so important. And to answer the first one, you have to first be very accurate in specify what the conclusion even is. Try that here. Specify the conclusion, and specify what it would mean for the conclusion to be wrong.

Look really close at the conclusion. It doesn't say, "CO2 will be reduced because of this product." It says "using this new concrete will reduce CO2."

If the conclusion is 'using the concrete will reduce CO2,' that conclusion would be wrong if 'using the concrete does NOT reduce CO2.'

The conclusion isn't wrong, really, if the concrete never gets used. Imagine the argument, "The minimum salary in the NFL is $620,000. So playing in the NFL is a good way to make a lot of money."

Does it strengthen the argument to say, "many people who, with hard work, could be talented enough to play in the NFL choose other career paths because they do not know how talented they could be."

Does that improve the argument that playing in the NFL is a good way to make money? Is someone's *awareness* of a strategy necessary for a strategy to be one that would work? Not at all. So whether people know about the option to use this material or not just doesn't matter to the truth of the conclusion.

Many industrialized nations are trying to reduce atmospheric concentrations of carbon dioxide, a gas released by the burning of fossil fuels. One proposal is to replace conventional cement, which is made with calcium carbonate, by a new “eco-cement.” This new cement, made with magnesium carbonate, absorbs large amount of carbon dioxide when exposed to the atmosphere. Therefore, using eco-cement for new concrete building projects will significantly help reduce atmospheric concentrations of carbon dioxide.

We need to strengthen the following:

using eco-cement for new concrete building projects will significantly help reduce atmospheric concentrations of carbon dioxide.

Using X will help reduce Y.

Can we strengthen the above by saying that people will use X?

No.

Let's look at the opposite of option B

Eco-cement is WEAKENED when absorbed carbon dioxide reacts with the cement.

In this case, people will probably not use eco-cement if
1. carbon dioxide reacts with the cement (we don't know that it does)
2. it becomes weakened to an extent that it doesn't remain usable for its desired purposes. (we don't know this too)

So, you can see that this variation of option B indicates that people will not use eco-cement only if we make the two jumps mentioned above.

On top of this, this variation indicates that people will not use the eco-cement. However, as we discussed, whether X is used or not has no impact on the statement "using X will lead to Y".

Thus, the variation of option B has no impact on the given argument.

For the same reasons, option B has no impact on the given argument.

A. this is an argument about how ecocement reduces the conc of CO2 in the atmosphere. we are not concerned about costs. just cause cost is high now and will fall in the future does not tell us about the effect ecocement has on CO2 concentration.

B. this again tells us about the reaction between ecocement and CO2, how ecocement is strengthened. but it does not strengthen (haha!) the argument about how its usage reduces the CO2 concentration.

C. so what? before it was a certain way, now its been developed into ecocement. also if ecocement is still not as good as regular cement maybe this choice weakens the argument.

D. YES! if the manufacture of ecocement itself uses less fossil fuels, thereby releasing less CO2 into the atmosphere than would otherwise have been the case, the CO2 levels will considerably drop. Moreover, this ecocement absorbs CO2 as well yeah? So both while being manufactured as well as while being used in buildings, theres a SIGNIFICANT drop in CO2.

E. if these people are unaware, how can ecocement be widely used and reduce CO2? weakener.