The folktale that claims that a rattlesnake's age can be determined

Question

The folktale that claims that a rattlesnake's age can be determined from the number of sections in its rattle is false, but only because the rattles are brittle and sometimes partially or completely break off. So if they were not so brittle, one could reliably determine a rattlesnake's age simply from the number of sections in its rattle, because one new section is formed each time a rattlesnake molts.

Which one of the following is an assumption the argument requires in order for its conclusion to properly drawn?

(A) Rattlesnakes molt exactly once a year

(B) The rattles of rattlesnakes of different species are identical in appearance

(C) Rattlesnakes molt more frequently when young than when old

(D) The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life

(E) Rattlesnakes molt as often when food is scare as they do when food is plentiful

srikalivarapu · Accepted Answer

the key conclusion -> each time a molt happens a new section is grown given the rattle is not so brittle.

(A) Rattlesnakes molt exactly once a year

Negate -> Molts more than once a year --so what ? each time a molt happens a new section is grown and age could be determined.

(B) The rattles of rattlesnakes of different species are identical in appearance

Negate --> the rattles of rattlesnakes a different species are NOT identical in appearance- so what ? as long as they molt on time with no brittle rattle the age could be determined.

(C) Rattlesnakes molt more frequently when young than when old

Negate --> Rattle snakes molt less frequently when young than when old so what ? as long as they molt on time with no brittle rattle the age could be determined.

(D) The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life

Negate --> The brittle factor is related to length of the rattle snake so what ? a close one. but the conclusion states the new sections of rattles are age determinant factors at every molt.

(E) Rattlesnakes molt as often when food is scare as they do when food is plentiful

Negate--> Rattlesnakes DONT MOLT often when food is scare as they do when food is plentiful so what ? if this happens a new section might not show up each time the snake molts which could screw up the math of age(we dont know how it is done) calculation. this goes against the conclusion " rattlesnake's age can be determined from the number of sections in its rattle" hence the answer correct answer is E.

CrackverbalGMAT · Answer

Hi Keya

Good question.

The question stimulus does not mention anything about the food or its availability. However, let us analyze the premises and the conclusion given in the stimulus.

Conclusion: If the rattles were not so brittle, one could reliably determine a rattlesnake's age simply from the number of sections in its rattle, because one new section is formed each time a rattlesnake molts.

Premises: The folktale that claims that a rattlesnake's age can be determined from the number of sections in its rattle is false, but only because the rattles are brittle and sometimes partially or completely break off.

Essentially, the conclusion is that except for brittleness, there is   no   other factor that prevents us from determining a rattle snake's age just by counting the number of sections in its rattle, since a new section is formed every time it molts (sheds skin). Therefore, the underlying assumption is that all other factors (apart from brittleness) have no impact on either the rattle sections directly, or on the molting of the snakes (this is important because a new rattle section is formed every time the snake molts, hence, anything that impacts the frequency of molting will impact the age obtained by counting the number of sections in the rattle).

Option (E) presents food as one factor that could potentially impact the frequency of molting, and states that it has no impact. This is consistent with our assessment above. The negation method also points to (E) as explained in an earlier post. Clearly (E) is the best answer available among the options.

Hope this helps.

sharathnair14 · Answer

It would be very easy to mark Options A & D if one doesn't understand the passage properly.

The Passage has an annoying structure. It has two derived statements. 
The author wants you to believe two things. 
 1)  That the folktale's claim is flase. (Counting the sections of rattle can help judge a snake's age) 
 2)  That this claim could be true if a particular scenario doesn't exist. (That the rattles are brittle)

Clearly, the 2nd statement is the main conclusion. 
A scenario that inhibits or causes this method (Counting) to fail would break the conclusion. Thus, ruling out such a scenario would be an assumption. 
Examples of such scenarios - 
 A.  Rattles are lost each time the snake molts. 
  B.  Molt process unusually takes place due to determinant factors (Environment, 
 Climate, etc. 
  The right Answer choice E rules out scenario B   with the availability of food becoming the factor. 
Choice C might seem like a trap choice to some, but snakes molting more frequently when young is more of a fact which can be foreseen and can be taken into consideration while calculating the age of the snake.

keyashah0312 · Answer

Can you plz help me that Why Option E is correct?

I mean what's the connection with food here?

unraveled · Answer

The folktale that claims that a rattlesnake's age can be determined from the number of sections in its rattle is false, but only because the rattles are brittle and sometimes partially or completely break off. So if they were not so brittle, one could reliably determine a rattlesnake's age simply from the number of sections in its rattle, because one new section is formed each time a rattlesnake molts.

Which one of the following is an assumption the argument requires in order for its conclusion to properly drawn?

(A) Rattlesnakes molt exactly once a year

(B) The rattles of rattlesnakes of different species are identical in appearance

(C) Rattlesnakes molt more frequently when young than when old

(D) The brittleness of a rattlesnake's rattle is not correlated with the length of the rattlesnake's life

(E) Rattlesnakes molt as often when food is scare as they do when food is plentiful

This question breaks the myth apart that external information is required in question that seek to either strengthen or weaken the argument. 
It was between D and E for me, unfortunately it was D for me.
No only i got confused by D but E had this food info that seemed to make no sense. Had the part " as they do when food is plentiful" not been there it would been easier for me to choose it over D. However, now i realise that If there's molting variability wrt to food the proportionality to calculate age fails to stand, breaking the argument.
In D, even if its related the calculation of age is still holds because its known that how age affects brittleness. But i would still not give it a thumbs up or down simply for the reason that it's still confusing. E, on the other hand is clear.

Answer E.

Freddy12 · Answer

GMATNinja   GMATNinjaTwo  Can you help with this Question?

GMATNinja · Answer

You're in luck: we covered this question in a YouTube video. Check out the 3rd question in  this video  for a full explanation.Enjoy, and let us know if that doesn't help!

HarishD · Answer

Classic example of a "Assumption PREVENT FROM WEKNESS" type assumption questions.

conclusion: Brittle is the reason which prevents age counting.

Option E) says Snake molts at the same rate, even if food is scare or plentiful. (I read this wrong and marked B)
 It protects from weakness of the conclusion and says "food is not the reason"

iabhish1509 · Answer

The argument says:

Support:  Rattles are brittle and sometimes break off. 
  Mini conclusion:  Therefore, the folktale that claims you can tell a rattlesnake's age by counting the rattle sections is false. 
  Main conclusion:  If rattles were not brittle, you could reliably determine a rattlesnake's age by counting the sections, because a new section is formed each time a rattlesnake molts.  
To reach the main conclusion, the argument needs to assume certain things.  One key assumption is that molting (shedding old skin) is consistent and not influenced by external factors, such as food availability.

-> If molting frequency changed based on how much food is available, the number of rattle sections wouldn’t reliably indicate age. That would break the conclusion of the argument.

Now, let's explain the statement " Rattlesnakes molt as often when food is scarce as they do when food is plentiful ":

Option (E) means that rattlesnakes molting rate doesn't depend on some external factors, it shed their skin (molt) at the same rate whether they have a lot of food or very little food.   
And the reason why Option A is wrong because -

Try negating option A.  
 
  If Option (A) was given that "Rattlesnakes molt exactly once in 6 months", then also we could be able to get to the conclusion. Hence we don't need this as our assumption.   
So, the correct answer is (E) because it ensures that molting is not influenced by food availability, which supports the argument.

RishiRamdani · Answer

What am I given :
1) Claim: rattlesnake's age can be determined from the number of sections in its rattle
2) This claim is false. Explanation : the rattles are brittle and sometimes partially or completely break off
3) Conclusion + new fact : if they were not so brittle, one could   reliably   determine a rattlesnake's age simply from the number of sections in its rattle, because one new section is formed each time a rattlesnake molts.

What am I asked: Find an assumption required for the conclusion to properly drawn.

(E) Rattlesnakes molt as often when food is scare as they do when food is plentiful

If rattlesnakes molt's frequency differs depending on different parameters, then the conclusion cannot hold because we cannot rely on the new section formed each time a rattlesnake molts to   RELIABLY   determine its age. Therefore, E is a necessary assumption.

To confirm it is the right answer, we can use the negation test:  (E) Rattlesnakes DO NOT molt as often when food is scare as they do when food is plentiful  => Confirms the explanation above and destroy the conclusion.

PriyankaGmatIMD · Answer

But why is A wrong. If it molts exactly one year , I can count no of rattles and that will give ne the age

Posted from my mobile device

GMATNinja · Answer

Be careful with the question itself: "Which one of the following is an assumption the argument   requires   in order for its conclusion to properly drawn?" In other words, do we NEED this assumption in order for the argument to work?

For choice (A), the answer is "no" because it doesn't matter whether rattlesnakes molt exactly once a year, twice per year, five times per year, once every two years, or whatever. As long as the rattlesnakes molt at some regular interval, the argument works, so (A) is not a REQUIRED assumption.

For more on that, please check out our video explanation of this question:  https://youtu.be/H7AyAmiIaBI?si=fECLagtdVBuUMigr&t=1309 .

pheemy · Answer

What I think 
The answer is E, here is why. 
 Question Stem  
We are looking for a necessary assumption to make the argument true.

The conclusion is saying that is the rattles of a rattle snake are not so brittle, one can reliably determine a rattles snakes age, why? - because a new section is formed when the rattle snake molts meaning sheds its skin or whatever that means. 
The argument that the author is making here is simply that the only reason we cant accurately determine the age of a rattle snake is because their rattles break easily and there really isnt any other reason that can make it also difficult to determine the age of a rattle snake.

Thats exactly what E tells us that the rattle snakes molt regardless of whether food is scarce or when food is plentiful. Meaning food is not a factor that changes the rattle snakes molting because if food does then itll be hard to determine the true age of the rattle snake even if the rattles were not so brittle. Thats how I understood it!!

The folktale that claims that a rattlesnake's age can be determined

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The folktale that claims that a rattlesnake's age can be determined

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