Wild cheetahs live in the African grasslands. Previous estimates of th

Question

Wild cheetahs live in the African grasslands. Previous estimates of the size that the wild cheetah population must be in order for these animals to survive a natural disaster in the African grasslands region were too small, and the current population barely meets the previous estimates. At present, however, there is not enough African grassland to support a wild cheetah population larger than the current population.

The statements above, if true, most strongly support which one of the following conclusions?

(A) Previous estimates of the size of the existing wild cheetah population were inaccurate.

(B) The cheetah’s natural habitat is decreasing in size at a faster rate than is the size of the wild cheetah population.

(C) The principal threat to the endangered wild cheetah population is neither pollution nor hunting, but a natural disaster.

(D) In the short term, the wild cheetah population will be incapable of surviving a natural disaster in the African grasslands.

(E) In regions where land is suitable for cheetah habitation, more natural disasters are expected to occur during the next decade than occurred during the past decade.

pqhai · Accepted Answer

Hi supergrad.

I'm glad to help.

THEORIES:
   Conclusion question. 
 Correct answer: 
Must pass the “Fact test”. Do not infer too far, just stick to premises.
Must show the main point, not just repeat the premises.
 Wrong answers: 
Pass the fact test, but only rephrase the premises (repeat one, two premises or combination of premises)
Out of scope or infer too far (not pass the fact test).

STIMULUS:  
Fact 1: Wild cheetahs live in the African grasslands.  Necessary condition. 
Fact 2: Previous estimates of the size that the wild cheetah population must be in order for these animals to survive a natural disaster in the African grasslands region were too small.  FACT 
Fact 3: The current population  barely meets  the previous estimates.  FACT 
Fact 4: At present there is  not enough African grassland  to support a wild cheetah population larger than the current population. -->   Necessary condition is not met.

ANALYZE THE STIMULUS:  
Fact 2 means previous cheetah population needed to survive a natural disaster was too small. 
Fact 3 means the current cheetah population is even smaller that that in the past. It means the current cheetah population is not enough to survive a natural disaster.
Fact 4 means the current cheetah population can’t become larger because there is not enough African grassland.  Fact 4 clearly states that the cheetah population is not increasing, at least in the short term.

Combine fact 2, 3, 4 we can say that in the short term, the wild cheetah population will be incapable of surviving a natural disaster in the African grasslands.

Thus, D is correct.

Hope it’s clear.

KarishmaB · Answer

You should try to think ahead of what you are expecting from your answer option.

Look at the argument:
Previous estimates of 'cheetah population required to survive a natural disaster' were too small. (e.g. Previous estimate - if there are 100 cheetahs, they can survive a natural disaster. This estimate is too small. You perhaps need at least 200 to survive a natural disaster)
The current population barely meets the previous estimates. (The current pop is barely 100)
At present there is not enough African grassland to support a wild cheetah population larger than the current population. (So the population can't increase in the short term)

What can you say from this? What does this lead to?

That in the short term, if there is a natural disaster, the cheetahs probably will not survive it. (Option D)

(A) Previous estimates of the size of the existing wild cheetah population were inaccurate. 
No. Previous estimates of 'cheetah population required to survive a natural disaster' were inaccurate. Not the estimates of current cheetah population.

(B) The cheetah's natural habitat is decreasing in size at a faster rate than is the size of the wild cheetah population.
The argument doesn't say that the natural habitat is decreasing. It only says that at present, it cannot increase. The rate of increase/decrease is anyway out of question.

dentobizz · Answer

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supergrad · Answer

if D is the answer can someone please explain how the passage supports the claim that the size of grassland and cheetah population is not increasing, the passage doesn't give any information on the trend

AmithKumarSingh · Answer

It not an easy task to get to the right conclusion here, thanks to the wordy premises

Facts and premises are explained well in above post. I will go for an example case

from the 1st statement it is clear that though Cheetahs population was less, the grassland area was good enough,if not great. Case1; in 10 sqkm area there are 20 cheetahs. Natural disaster-->very low chances that many cheetahs getting effected, but still the effect is huge as population is less. Case2: Huge reduction in grassland area: 5 sqkm existing. Chettahs-16 (less than earlier 20) But here if natural disaster occurs, more cheetahs will get affected as they are confined in less area to save their lives. and at the same time more cheetah's are influenced by the disaster coz of limitations. So I went with D as it brings out this case

If it is not clear, plz let me know, i will try up presenting in a better way.

EMPOWERgmatAllenT · Answer

Hi mahendru1992,

Happy to help. What you're doing is saying that the information in the prompt supports the idea that the Wild Cheetah won't survive a natural disaster beyond just in the short-term. So how is it that we can only infer that its short-term?

The distinction comes down to knowing EXACTLY what this question is asking for. This is an inference question,  which means we're asked to find an answer that HAS TO BE TRUE.

It comes down to this: just ask yourself, "do we know for sure that the Wild Cheetah population is incapable of surviving a natural disaster in the short-term?" If you're thinking the incapability is even further than short-term, than the answer to this question would HAVE TO BE: YES!

To use a different example to demonstrate the exact same logic why D has to be right: let's say we know that somebody ran at least 10 miles. Do we know that the person ran at least 1 mile? Yes. Same exact logic. If the data supports a greater range, you can infer a smaller part of that range.

EMPOWERgmatAllenT · Answer

Hi mahendru1992,

I think you may have mis-read. The fact was that he ran AT LEAST 10 miles. If he ran at least 10 miles, do we know that he ran at least 1? Of course. See the distinction?

EMPOWERgmatAllenT · Answer

Hi mahendru1992,

No trouble at all. Let's lay out all of the facts once more, and you'll see how this goes beyond JUST the present moment:

Previous estimates of the cheetah to survive a natural disaster in the African grasslands region were too small.  That means we know the number needs to be bigger. 
The current population barely meets the previous estimates.  That means that the current population is WAY below what it needs to survive if it doesn't meet the previous estimates which were already too low. 
At present, there is not enough African grassland to support a wild cheetah population larger than the current population.  This tells us that there is not even enough grassland to support a population any bigger than it is today.

Given those facts, is there any way the wild cheetah could survive a natural disaster of the short-term (say the next few months, maybe even a year?). No way. That's why D has to be right.

I think that the source of your doubt has to do with your definition of short-term. If you were thinking of it as something on the order of say 2-5 years, then, you're right, we can't infer that.

pate13 · Answer

While I understand what this question is trying to say, and I answered it correctly, I think this is a poor question. Is it really true that the population would be INCAPABLE of surviving a natural disaster? Even if there is a .000001% chance of the population surviving, it still isn't incapable of surviving. Absolute language on CR questions is usually a major indicator that an answer choice is wrong. I think D would be a lot better stated, and more accurate, if it said "In the short term, the wild cheetah population would probably not survive a natural disaster in the African grasslands."

KyleWiddison · Answer

You are correct that the answer for these "draw a conclusion" questions will often be weak or trivial, but that is not a requirement. The real standard is to stay close to the precise wording of the argument and avoid answer choices that are STRONGER than the premises of the argument.

If you look at the premises here, you will find very strong language throughout: "size...must be...to survive", "too small", "not enough". These are very definitive statements and the answer choice isn't stronger than those premises.

That said, I agree that on the GMAT you would probably see a bit softer language, similar to what you have suggested. A good example of this is #103 - the Patria trade embargo question. The correct answer states: "Any trade embargo against Patria would be likely to fail at some time." Instead of absolute language like "will fail" the GMAT used "would be likely to fail".

KW

talismaaniac · Answer

Is my reasoning faulty? The estimated population size for wild cheetah to survive natural disaster was small. And current population is below the estimate, and African grassland cannot sustain even that.
First. Congrats all the existing wild cheetahs. This is great news for you. Earlier you had your competition. Now you are few and free. Whoa!
However, what is the African Grassland has to do with that? May be to accommodate the Cheetahs. Wait! So do you mean that earlier the African Grassland was able to accommodate the estimated population, and now the current population is even low, and the Grassland is not even able to support that.
Therefore, the grassland must be shrinking, that too at a faster rate.

D says natural disaster in the short term. However, what has the natural disaster to do with the size of grassland? Why was natural disaster mentioned in the first place?

KarishmaB · Answer

I think you haven't understood the argument properly.

Wild cheetahs live in the African grasslands. Previous estimates of the size that the wild cheetah population must be in order for these animals to survive a natural disaster in the African grasslands region were too small,

The previous estimates were too small. That means they were not accurate. The actual value of "the actual size that the wild cheetah population must be in order for these animals to survive a natural disaster in the African grasslands region" should be greater.

and the current population barely meets the previous estimates,

The current population is less than the pervious estimates.

At present, however, there is not enough African grassland to support a wild cheetah population larger than the current population. 
But the grassland can support only current population, not larger.

So what will happen if there is a natural disaster in the near future?

The cheetah population is much less than that required to survive a natural disaster. So it will probably not survive. 
Hence answer is (D)

What is the relevance of "short term"? We can't say the same thing about long term (because the cheetah population might grow).

GDT · Answer

(A) Previous estimates of the size of the existing wild cheetah population were inaccurate. estimates were of wild cheetah popn. required to survive a natural disaster not of the actual existing popn.

(B) The cheetah’s natural habitat is decreasing in size at a faster rate than is the size of the wild cheetah population. We don't know of the comparative rates but only that both these rates are falling

(C) The principal threat to the endangered wild cheetah population is neither pollution nor hunting, but a natural disaster. Whether natural disaster is a principal threat or not is not mentioned or pointed out in the stimulus

(D) In the short term, the wild cheetah population will be incapable of surviving a natural disaster in the African grasslands. Since we know that at present wild cheetah popn. barely meets our estimate of min. popn. required to survive the natural disaster, so in case of such a happening now as per stimulus we can conclude that they won't be able to survive

(E) In regions where land is suitable for cheetah habitation, more natural disasters are expected to occur during the next decade than occurred during the past decade. Nothing is mentioned in the stimulus in this regard

bidskamikaze · Answer

- Previous estimates of the size that the wild cheetah population were too small
- Current population barely meets the previous estimates. 
- At present, there is not enough African grassland to support a wild cheetah population larger than the current population.

CONCLUSION: (D) In the short term, the wild cheetah population will be incapable of surviving a natural disaster in the African grasslands.

Answer D.

agrasan · Answer

Hi experts  KarishmaB   MartyMurray   DmitryFarber

Could you please explain why option B is wrong?

(B) The cheetah's natural habitat is decreasing in size at a faster rate than is the size of the wild cheetah population.

When previous estimates were rolled out, it was expected that Cheetahs will be able to survive in  a given area of grasslands , now current population is lower than those estimates and grassland is not able to support population larger than current one. Can't we infer that grassland area has also shrunk?
 Is this inference wrong because we don't know what is the grassland area for current population  (as the argument only tells us about what happens when population becomes larger than current) ?  It might have remained unchanged since previous estimates were rolled out.

Please let me know where I am faltering.

KarishmaB · Answer

Previous estimates had nothing to do with the area. They were the number of cheetahs that must be there to survive a disaster. Whether the area was enough to support this population estimate, we are not given.
We are given that the estimate is too small. We are also given that the area cannot support more than current population which is perhaps slightly less than or almost equal to the previous estimate. 
We cannot say that the natural habitat is decreasing - there is no such info given.

Wild cheetahs live in the African grasslands. Previous estimates of th

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Wild cheetahs live in the African grasslands. Previous estimates of th

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