In parts of the Caribbean, the manatee, an endangered marine mammal, h

This is a clear E.

A: Many tourists are uninterested, but not all. The passage says that tourist interest is high so quite possibly a small niche of tourists would be willing to pay top dollar. This doesn't negate the plan. Additionally this choice goes against a premise that tourist interest is high, so Id avoid this choice. (regardless, it can be proved that just because many are uninterested, this does not mean all and tourist interest could still be high).

B: Doesn't negate the plan.
C. Doesn't negate the plan.
D. Maybe, but this doesn't mean that the plan wouldn't work. In fact if there aren't enough hunters then this would suggest that hunters would then get paid even more. Simply put high demand for a small supply would increase the amount paid and would definitely probably improve the chances of manatee survival since being a guide is profitable.

E. key word here "fragile." This suggests that the boats have a direct effect on the manatees safety. So if former hunters threaten the manatee's safety w/ big boats, this negates the argument that the plan will work.

Premise - In parts of the Caribbean, the manatee, an endangered marine mammal, has long been hunted for its meat. Having noted the manatee hunters’ expert knowledge of manatees’ habits, local conservationists are encouraging the hunters to stop hunting and instead to take tourists on boat rides to see manatees.

Conclusion - Tourist interest is high, so the plan has promise of achieving the twin goals of giving the former hunters a good income and helping ensure the manatees’ survival.

Anything which weakens the conclusion is our answer

A)Many tourists who visit these parts of the Caribbean are uninterested in manatees and would not be willing to pay what the former manatee hunters would have to charge for boat rides to see manatees. (Wrong as it is already given in the passage that Tourist interest is high)
B) Recovery of the species would enable some hunting to continue without putting the manatees’ survival in jeopardy again. (Neutral statement)
C) In areas where manatees have traditionally been hunted for food, local people could easily replace the manatee meat in their diets with other foods obtained from the sea. (Rather than weakening it strengthens the conclusion, eliminate)
D) There would not be enough former manatee hunters to act as guides for all the tourists who want to see manatees. (Not relevant)
E) To maintain their current income, manatee hunters who switched to guiding tourists would have to use far larger boats and make many more trips into the manatees’ fragile habitat than they currently do (This is our answer, if the incentives the hunters receive as tourist guides is less or the trouble is more they might not switch the occupation)

Hi,
The passage talks about tourist interest being high. It doesnt say categorically that the interest is high in mantees. It might be the case that the tourist interest is high in generally in terms of visiting the Caribbean.
This is what I thought while choosing A. Can you please let me know where I went wrong.

Hello ameya

Yes, A is tempting but wrong. The conclusion mentions the twin goals:
(1) giving the former hunters a good income and
(2) helping ensure the manatees’ survival

Note: good income does not mean a lot of money.

Option A:
Many tourists who visit these parts of the Caribbean are uninterested in manatees and would not be willing to pay what the former manatee hunters would have to charge for boat rides to see manatees.

Let analyze A:

- "many tourist are not interested" does not mean former manatee hunters will not have customers. i.e, 100 tourists, 50 uninterested (50% clearly means "many"), so former manatee hunders still have 50 customers. --> goal #1 met.
Note: We can't infer that the former manatee hunters do not have good income by serving 50% customers. Thus, "many" is a weak assumption.
- Fewer tourists means the manatees' habitat will be preserved better --> goal #2 met

Thus, A is not the correct answer.

Hope it helps.

I think you've explained why it is irrelevant if 'many tourists are not interested' - as you point out, it is a premise of the argument that 'Tourist interest is high'. A premise is a fact; it must be true. So even if many people are not interested, we know as an absolute fact that tourist interest is high, so it must be true that many people are interested. And as long as many tourists are interested, the plan can succeed.

This is a very important point in GMAT CR. When you are trying to weaken an argument, you are never trying to disprove the premises of the argument. Any answer that appears to contradict a premise cannot be the right answer (and if you think an answer contradicts a premise, you've misinterpreted what the answer choice means). Many trap answers in questions like these are answers which superficially appear to contradict a premise, and you can rule those answers out immediately.

In parts of the Caribbean, the manatee, an endangered marine mammal, has long been hunted for
its meat. Having noted the manatee hunters’ expert knowledge of manatees’ habits, local
conservationists are encouraging the hunters to stop hunting and instead to take tourists on boat
rides to see manatees. Tourist interest is high, so the plan has promise of achieving the twin goals of
giving the former hunters a good income and helping ensure the manatees’ survival.

Which of the following, if true, raises the most serious doubt about the plan’s chance of success?

By taking the tourists on excursions into manatee habitats instead of hunting the manatees, hunters can continue to make good income but not harm the manatees.

A. Many tourists who visit these parts of the Caribbean are uninterested in manatees and would
not be willing to pay what the former manatee hunters would have to charge for boat rides
to see manatees. We're told that tourist interest is high.

B. Recovery of the species would enable some hunting to continue without putting the
manatees’ survival in jeopardy again.
This doesn't address whether tours do more or less harm compared to hunting.

C. In areas where manatees have traditionally been hunted for food, local people could easily
replace the manatee meat in their diets with other foods obtained from the sea.
This doesn't address the relative damage of tours to hunting.

D. There would not be enough former manatee hunters to act as guides for all the tourists who
want to see manatees.
This doesn't affect the argument that tours do less damage than hunting.

E. To maintain their current income, manatee hunters who switched to guiding tourists would
have to use far larger boats and make many more trips into the manatees’ fragile habitat
than they currently do.
If the tours damage the habitat the hunters are doing equal or greater damage to manatees.

You are saying exactly the opposite of what is required to weaken an argument. The best way to weaken an argument is to weaken the premises.
Even this question says so itself -"Which of the following IF TRUE ...."
Heck !! GMAT itself is telling the test taker to take the answer choices in given options as "True".
Perhaps you have forgotten that NEW INFORMATION can be liberally used in weaken,strengthen,assumption,justify, paradox, and evaluate the argument family of question.
A is incorrect because of contraposition in logic :- MANY IS NOT THE LOGICAL OPPOSITE OF ALL
The logical opposite of ALL is NOT ALL
In syllogistic and propositional logic ==>Many = some
So Option A is saying some tourist might not want to see the animal. This does not weaken the argument.
The correct answer is E but not because of the reasons you are telling. I humbly suggest you take a quick look into tautology and truth-tables to rectify your misconception.

As far as the GMAT is concerned, what you are saying is not true. From the tone of your post, I don't get the impression you're interested in a civil conversation, so I won't try to have one, but if you're interested in further explanation, perhaps you can find another GMAT expert who is willing to discuss this with you.

I'm only replying to affirm that what I wrote above is correct, at least as far as GMAT CR arguments are concerned, for the benefit of other test takers who might read this thread.

I am very humbly and civilly resting my case. Your answer is wrong. I have no doubts about it and perhaps a quick brushing of your concept will make you realise that you made a novice mistake in evaluating, analysing and applying the concept of GMAT logic and reasoning. If you still insist that you have NOT made the gravest and most unpardonable error regarding the use of new information in weaken questions, then I too have nothing to add to this discussion. You can confirm your mistake by contacting a unbiased referee or expert from this forum (only if you are interested to)

Like the rule of thermodynamics doesn't change whether you are talking about a small test-tube filled with gas or a carnot engine or a heat sink or the entire universe, similarly the rules of logic doesn't change whether you are talking about philosophical, mathematical, propositional, syllogistic, GMAT, LSAT or any other kind of logic. Thats the beauty of logic that along with math, it is probably the only subject that does not have weird exceptions when it comes to its rules. LOGIC NEVER CHANGE.


HOWEVER FOR THE BENEFIT OF OTHER USERS/READERS COMING ACROSS THIS QUESTION, I MUST ADD THAT YOUR REASONING IS ABSOLUTELY INCORRECT AND HENCE SHOULD NOT BE FOLLOWED. (AT LEAST FOR THIS QUESTION FOR THE TIME BEING!!)
IN THE PRESENT FORM THE ABOVE MENTIONED ANSWER IS MOST HALF BAKED AND ILL-INFORMED POST IN THIS ENTIRE THREAD AND SHOULD BE AVOIDED WITHOUT FAIL.

@IanStewat sir,

Sir I just wanted to clear some air here. I feel that you and LogicGuru are both correct. For example for the question below:

Major airlines will purchase many of the new aircrafts capable of carrying more than 500 passengers on transcontinental and transoceanic flights. These airlines currently rely on "hub and spoke" systems of routing, in which large planes, which can seat 400 people and are capable of transoceanic flight, fly into hubs that have runways sufficiently long to handle them. From there, passengers are dispatched to local airports on connecting flights on small planes. With takeoff and landing time slots almost completely booked at most hubs, and little new runway construction expected, airlines will want to expand the volume of passengers they can fly in a given time slot.

The argument above would be most weakened if which of the following were true?

A. The new 500 seat aircraft cost more per seat than existing aircraft
B. Air traffic control systems at most hub airports cannot handle any more flights per hour than they currently do
C. The new 500 seat aircraft require boarding times substantially longer than those of existing aircraft
D. Small passenger aircraft, capable of efficient transcontinental and transoceanic flight and able to land on short runways, have come into service
E. Transoceanic air flights are currently running at near maximum capacity


OA is D.

Here D is giving us some new information that can be used to weaken the argument. I feel that LogicGuru's explanation is correct in the sense that option A is incorrect because opposite of 'All' is ' Not All' which basically leads to some/many. Since even if some people lose interest, even then it is not weakening the argument.

Kindly provide some insight since you guys are the experts!

This is a peculiar conversation. I have the impression that LogicGuru has not understood what I've written, especially when he claims I said anything "regarding the use of new information" in a CR question. And Raghav, I appreciate your effort to be diplomatic, but when you say that LogicGuru is (partly) right when discussing "new information", you're saying he is right about a straw man, about words he put in my mouth, words that I never said. If you read my original posts, I never said anything about "new information".

In case anyone else has misunderstood what I wrote, I'll say it again, with more detail: in a weaken CR question, the premises in the stem should always be taken as absolute facts. The correct answer, the answer which weakens the argument, is never correct because it contradicts or disproves one of the facts stated in the stem. To illustrate with a very simple example, suppose you have this CR stem:

Tim will make lemonade at a cost to him of $1 per glass. Because he will sell the lemonade at $2 per glass, he expects to make a profit. Which of the following, if true, would suggest Tim is incorrect?

On the GMAT, no answer choice can possibly say "Tim will actually sell the lemonade at $0.75 per glass". That is, an answer choice can never say "we were lying to you in the stem above and in fact something completely different is true". Anything stated as a fact in the stem is an absolute fact and cannot be false no matter what an answer choice says. The correct answer to this question would be something more like "Tim will only sell one third of the lemonade he produces". That is new information, and obviously you often get new information from the answer choices in such questions. But it is new information that in no way contradicts the other information you've been given. All of the information in the stem and in that answer choice is logically consistent. The same is true in the original question, by the way: tourist interest can be high even if many tourists have no interest. There is no logical inconsistency there - we already know that many tourists do have interest. But you could not possibly even see an answer choice in the original question which read "there is no tourist interest", because that would directly contradict a fact in the question stem.

What I'm saying is fundamental to GMAT CR, and is in no way controversial; any other reputable GMAT expert will tell you exactly the same thing. If LogicGuru wishes to continue to insist I'm wrong about this, then there is a straightforward way for him or her to prove that: find a single official CR weaken question where the correct answer (or any answer choice) contradicts one of the factual premises stated in the stem. Or, since it will take an eternity to find such an example, a faster way would be to ask any other GMAT expert, if you are not inclined to believe me.

In parts of the Caribbean, the manatee, an endangered marine mammal, has long been hunted for its meat. Having noted the manatee hunters’ expert knowledge of manatees’ habits, local conservationists are encouraging the hunters to stop hunting and instead to take tourists on boat rides to see manatees. Tourist interest is high, so the plan has promise of achieving the twin goals of giving the former hunters a good income and helping ensure the manatees’ survival.

Which of the following, if true, raises the most serious doubt about the plan’s chance of success?

A. Many tourists who visit these parts of the Caribbean are uninterested in manatees and would not be willing to pay what the former manatee hunters would have to charge for boat rides to see manatees.
The choice is alluring since it questions the feasibilty of the plane by providing a point that the hunters will not be earning as mush as they are doing now.But we cannot select this until reading all the choices.and after reading all the choices we find that option E is a better choice.Since the ultimate goal is to protect mantee and not provide employment to the hunters.

B. Recovery of the species would enable some hunting to continue without putting the manatees’ survival in jeopardy again.
out of the current scope

C. In areas where manatees have traditionally been hunted for food, local people could easily replace the manatee meat in their diets with other foods obtained
from the sea.
This is actually a strengthener because is supports the plan.

D. There would not be enough former manatee hunters to act as guides for all the tourists who want to see manatees.
This point does not weakens the point because other hunters can be trained easily to act as travel guides.

E. To maintain their current income, manatee hunters who switched to guiding tourists would have to use far larger boats and make many more trips into the manatees’ fragile habitat than they currently do.
Correct answer since not only the hunters turned guide would not be earning as much as they are earning currently but also they would have to use bigger boats to make up for their profits.Bigger boats are threat tho the fragile natural habitat of mantee.

This is an exam pack 1 question please change the tag.
Thank you

a choice which is relevant but not strong enough to affect the argument is a trap . this trap is popular in og and gmatprep questions.

this trap is normally not enough quantitatively . if "most"not "many" is used, choice A can be correct.

Straight E.....'Fragile' word in option E makes all the difference.

What would be the best way to approach weaken questions? Consider every argument as a cause -effect relationship or just look for an option, which is the negation of the conclusion of the argument??

Posted from my mobile device

I am no expert but can certainly suggest. In strengthen/weaken type questions, it is important to attack the missing link between the premise and the conclusion.
Important point to remember is that the answer choice that weakens the conclusion does not have to be necessarily true 100 percent of the times.
So, figure out the conclusion of the argument and then attack the missing link to negate the conclusion.

Thanks !
Please press kudos if my response helped you in any way !