After a number of migrant fishermen at the Rotunda Beach pier got sick

Question

After a number of migrant fishermen at the Rotunda Beach pier got sick from consuming locally fished hermit crabs, the Rotunda Beach city authorities posted signs cautioning against the consumption of the crabs. Tests revealed that the crabs were high in prestic acid, a dangerous chemical. But a marked decline in the number of goldfish found by the beach has led to the removal of the warning signs.

Which of the following, if true, would best explain the removal of the signs?

(A) Goldfish found off Rotunda Beach cause hermit crabs to excrete prestic acid.

(B) The amount of prestic acid produced by an individual goldfish has a direct positive correlation with the density of the goldfish population in that goldfish’s immediate vicinity.

(C) Goldfish consume various parasites that often contain prestic acid.

(D) Rotunda Beach is notoriously polluted.

(E) Goldfish would not be able to inhabit the waters off Rotunda Beach if those waters were not saturated with a precise mixture of acids, including prestic acid.

TGC · Accepted Answer

After a number of migrant fishermen at the Rotunda Beach pier got sick from consuming locally fished hermit crabs, the Rotunda Beach city authorities posted signs cautioning against the consumption of the crabs. Tests revealed that the crabs were high in prestic acid, a dangerous chemical. But a marked decline in the number of goldfish found by the beach has led to the removal of the warning signs.

Premise: High prestic Acid in Hermit crab =>People got sick => Caution signs against Hermit Crabs
Conclusion: Decline in GF => Removal of signs.

Now how does conclusion is linked with premise in the stimulus , is what we have to answer .Because conclusion mentions GF and premise mentions HC.So there must be some relation between GF and prestic acid.
 
Which of the following, if true, would best explain the removal of the signs?

Goldfish found off Rotunda Beach cause hermit crabs to excrete prestic acid.
 This shows that signs shouldn't be removed because GF decline =>HC will less excrete prestic acid => People Sick 
The amount of prestic acid produced by an individual goldfish has a direct positive correlation with the density of the goldfish population in that goldfish’s immediate vicinity.
 If Density of GF directly proportional to the Prestic acid , the according to conclusion 
GF decline => Density of GF declines => Less Prestic acid => HC safe =>People will not get sick => Removal of signs. 
Goldfish consume various parasites that often contain prestic acid.
 Out of scope, we talking about Acid not parasites 
Rotunda Beach is notoriously polluted.
 Out of scope 
Goldfish would not be able to inhabit the waters off Rotunda Beach if those waters were not saturated with a precise mixture of acids, including prestic acid.
 Not related to argument

Hope it helps !!!

himanshujovi · Answer

I agree with your point. How is B in anyway related to crabs

shankyGMAT · Answer

First of all lets see why A is incorrect. According to this statement, more goldfish => more excretion of prestic acid(ie less retention). Thus if goldfish population declines retention of prestic acid in hermit crabs will increase and thus the danger is still there.

We can easily eliminate C & D as they are out of scope.

Now both B & E are assuming that prestic acid content in water is directly proportional to the acid content in crab. But E goes too far to say that "goldfish would not be able to inhabit at all" while the argument just mentions that the goldfish population has just declined.

hence (B) is correct

ssriva2 · Answer

I think B is not best among the answer choices.
In B we are taking an assumption that Crabs are in the vicinity of Goldfish.It may be a condition where Goldfish reside on east shore and crabs on west shore.
In A ,we are directly told that goldfish is responsible for excretion of prestic acid in crabs so it satisfies both premises.I think A is more appropriate than B.
Can anyone still explain why B is correct?  KyleWiddison   tuanquang269 
 mikemcgarry  ,I need your help here !

debaratidg · Answer

according to me answer is  B

I was confused between E and B and A.

A. Goldfish found off Rotunda Beach cause hermit crabs to excrete prestic acid.  Here, Goldfish OFF the beach not BY the beach cause hermit crabs to excrete prestic acid. So if the population has gone down. Crabs wont excrete but they would still contain prestic acid. So A is out

E. Goldfish would not be able to inhabit the waters off Rotunda Beach if those waters were not saturated with a precise mixture of acids, including prestic acid  Hmm this one felt tricky. Okay suppose the mixture contains 5% P acid. Now, there is 4% P acid and G fish can't survive without 5% P acid, BUT Acid still remains in the water for the crabs to intake, hence E is out.

B. The amount of prestic acid produced by an individual goldfish has a direct positive correlation with the density of the goldfish population in that goldfish’s immediate vicinity.  Now, if this correlation is correct, i.e. Amt of P acid ---> dependent on amt/density of pop of G fish, then Less G ---> Less P. So B seems legit

OA =  B

arhumsid · Answer

A. Goldfish found off Rotunda Beach cause hermit crabs to excrete prestic acid.
Its only telling us that Goldfish is on our side. It helps in reducing prestic acid's level in the crabs. But why should the warning signs be removed?

B. The amount of prestic acid produced by an individual goldfish has a direct positive correlation with the density of the goldfish population in that goldfish’s immediate vicinity.
This doesnt talk about crabs at all. Though Goldfish is important, we need to assure that crabs are not consumed. Doesn't help

C. Goldfish consume various parasites that often contain prestic acid.
This makes things worse! If this is the case, Goldfish can eat as many crabs as it wants now. As a result it should grow in number.

D. Rotunda Beach is notoriously polluted.
So what? Way out of scope!

E. Goldfish would not be able to inhabit the waters off Rotunda Beach if those waters were not saturated with a precise mixture of acids, including prestic acid
This makes sense.
Please note- precise mixture of acids is needed for the Goldfish to survive.
Now, Since the warning signs were put up, the levels of prestic acid must have gone up because of the unchallenged growth of crabs, thereby going beyond whats needed by our Goldfish. So, remove the warning so that the crabs are again hunted and level of prestic acid comes down.

Hence, ill go with E.

But hold on! We are saving Goldfish at the expense of our fishermen's health!!

tuanquang269 · Answer

The argument: consuming hermit crabs makes people got sick => authorities posted warning sign
Hermit crab excrete prestic acid which is toxic to human
The conclusion: Decline number of GF found off the beach => remove sign of caution

Scope: Hermit crab, prestic acid need connect to reasons of decline of GF

Nevernevergiveup · Answer

After a number of migrant fishermen at the Rotunda Beach pier got sick from consuming locally fished hermit crabs,

the Rotunda Beach city authorities posted signs cautioning against the consumption of the crabs.

Tests revealed that the crabs were high in prestic acid, a dangerous chemical.

But a marked decline in the number of goldfish found by the beach has led to the removal of the warning signs.

Which of the following, if true, would best explain the removal of the signs?

A. Goldfish found off Rotunda Beach cause hermit crabs to excrete prestic acid.
 (If Goldfish causes crabs to excrete acid then their present should reduce prestic acid and cause removal of warning signs.
but instead their absence seemingly resulted in the same. This further exacerbates the paradox adding more confusion.)

B. The amount of prestic acid produced by an individual goldfish has a direct positive correlation with the density of the goldfish population in that goldfish’s immediate vicinity.
(if  goldfish population     ∝    amount of prestic acid 
then decline in gold population indicates decline in the amount of prestic acid.
that is the reason why warning signs against eating crabs is removed since the amount of prestic acid reduce considerably.
This explains the paradox)

C. Goldfish consume various parasites that often contain prestic acid.
 this does not explain why it is acceptable to eat crabs now.

D. Rotunda Beach is notoriously polluted.
 This does not provide any useful information.

E. Goldfish would not be able to live in the waters off Rotunda Beach if those waters were not saturated with a precise mixture of acids, including prestic acid
 (This is a double negative. 
This means that If those waters are saturated with mixture of acids including prestic acid then Gold fish can live in waters off Beach.
so if Gold fish is decreasing then those mixture of acids is decreasing in content.
but
mixture of acids is not the same as prestic acid as it is possible that the mixture of acids may not be as harmful as prestic acd.
since we don't have info whether mixture is as harmful or harmless compared to prestic acid, we cannot infer any info which relates this info to do with crabs infection and removal of warnings.)

RatneshS · Answer

A very good question. Works on prethinking and correlation 
Crabs have acid inside them and people are getting sick eating the acid inside the crab

Prethink--how is goldfish related to crab
assumed-> crab eats goldfish

question--> If crab eats goldfish, why has officers remove the caution that crabs are harmful??
crabs eat goldfish// farmers eat crabs--> population of crabs is maintained

If farmers wont eat crabs--> more crabs and thus less goldfish

Only B says this.

redskull1 · Answer

I want a kudos I am telling you!!!!

Gist : Crabs have PA.Dangerous.Less goldfish less PA in crabs (or in general).Hence sign removed

We have to find the link between crabs and PA.

A =  Goldfish cause crabs to excrete PA .Think of the various situations possible here.The crab would excrete PA.Now we must assume that the PA excreted affects the crab present.We have to assume that the crabs live near the PA excreted.Or they consume the PA.

Point is we have to make pretty big assumptions here.Also I can think of this being a weakener to the statement "the sign has been removed" because if the crab doesn't excrete PA then the PA is present in the crab which we consume.Hence we cannot explain removing the signs.

B = When GF population prestic conc falls.

B as you may see is far neater.B's somewhat implied assumption is (The crabs live in an area of PA which is a sensible assumption to make given the circumstances).

vishumangal · Answer

I guess there are few questions from Veritas which are not upto the GMAT level. This is one of them. It makes a test taker think of assumptions which are not obvious. Assumptions may apply or may not. There are also few questions below which are not upto the standards.
https://gmatclub.com/forum/in-the-two-y ... 47485.html
https://gmatclub.com/forum/densmore-com ... 46595.html
https://gmatclub.com/forum/in-november- ... 24858.html

Are Real GMAT CR questions will never contain two or three option right

udaypratapsingh99 · Answer

The solution to this question requires assumptions. There can be multiple assumptions leading to different answers; thus, I find this question inappropriate. E comes close but require one unclear assumption, while B require even more complex more unclear assumptions.

Dharmilshah · Answer

KarishmaB 
Can you please explain why A isn't the correct choice?

MartyTargetTestPrep · Answer

(A) could be the correct choice.

(A), (B), and (E) are all arguably correct.

This question is a mess.

YashYashkratos · Answer

Answer is a bit too extreme - i chose B because i could not see why others were a good option however jump taken in B is a bit too far, the assumption we have to make here that hermit crabs get their chemical from gold fishes is a bit unfair just on the basis of the question.

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After a number of migrant fishermen at the Rotunda Beach pier got sick

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