GMATPrep -- Assumption -- monster (expert comment please)

[GMATMadeEasy]

Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through dieting, their metabolisms generally remain unchanged. They will thus burn significantly fewer calories at the new weight than do people whose weight is normally at that level. Such newly thin persons will, therefore, ultimately regain weight until their body size again matches their metabolic rate.

The conclusion of the argument above depends on which of the following assumptions?

(A) Relatively few very overweight people who have dieted down to a new weight tend to continue to consume substantially fewer calories than do people whose normal weight is at that level.
(B) The metabolisms of people who are usually not overweight are much more able to vary than the metabolisms of people who have been very overweight.
(C) The amount of calories that a person usually burns in a day is determined more by the amount that is consumed that day than by the current weight of the individual.
(D) Researchers have not yet determined whether the metabolic rates of formerly very overweight individuals can be accelerated by means of chemical agents.
(E) Because of the constancy of their metabolic rates, people who are at their usual weight normally have as much difficulty gaining weight as they do losing it.

OA is A

Few comments: Question is hard with the way they have constructed and took me long time to paraphrase and got to its skeletpon. It gives a good insight how a question can be turned into a complicated one. I could come down to A and D and chose the wrong answer even after I had predicted something close to the correct answer choice.

Neverthless, on a second analysisit was more puzzling. I do understand the correct answer and can feel the author making this appropriate assumption. I hope no one ever did say so in reality otherwise overweight people might have felt helpless. Anyways.

Question:

1. Isn't the answer choice D a protector of the argument that mean if negated , it destroys the argument: (simplfiied form)
a new chemical agent is found that can accelerate the metabolism rate. so "such newly thin person" won't get overweight ultimately. woww... the author of the argument is in trouble.

2. Well, to argue a bit more and to ensure I have not misunderstood, i put C also for discussion here for everyone's benefit.I see this as a weakener in its stated position so can't be a contendor even. If it iw energy consumer and not the actual weight that is decisive factor, then gaining weight depends on eating factor .

Negated statement : the amount of burnt calory is determined more by weight than by energy consumed.

that means two cases (overweight who has got new weight and someone with normal weight at that level) have different metabolism so it strengthens the argument.So wrong.

help please.

[Tani]

Conclusion: very overweight people with low metabolisms who lose weight through dieting will regain it

Evidence:
1. People who lose weight by dieting do not change their metabolisms.
2. people with low metabolisms will burn fewer calories than people at the same weight who have normal metabolisms.

Assumption: the overweight losers will not eat fewer calories than will people with normal metabolisms and therefore will put the weight back on. Answer A

Try denying A. If you say the overweight losers WILL consume many fewer calories than those with normal metabolisms, then they won't gain weight. That kills the argument, therefore it is a necessary assumption.

[GMATMadeEasy]

i am with you so far and goes with the same reasoning.

But what treatment to give to answer choice D as I am struggling to eliminate it on solid grounds. Though when I look into argument writer's brain , i can see A.

[GMATGuruNY]

i am with you so far and goes with the same reasoning.

But what treatment to give to answer choice D as I am struggling to eliminate it on solid grounds. Though when I look into argument writer's brain , i can see A.

One word can make an answer choice wrong. Here's the negation of answer choice D:

Researchers have determined whether the metabolic rates of formerly very overweight individuals can be accelerated by means of chemical agents.

Note the ambiguity of the word whether. If the researchers have determined that the metabolic rates cannot be accelerated, then the conclusion of the argument -- that the dieters will gain back the weight -- is strengthened. Since the negation of the correct answer choice must invalidate the conclusion, answer choice D is not the necessary assumption.

[tanviet]

at easy question, we can figure out the assumption immediately after you finish reading the argument or you can easily realize an asspmption among anwerchoice.

in harder question, you see nothing when you read answer choices. mode to attack is do negation each answer choices to see whether the nagation affect. Asssumption which is hard is DEFENDER ASSUMPTION-this concept can be learnt from CRITICAL REASONING BIBLE (but make it simple, dont read total of the book-some part of the book is long and not effective) but remember correct choice must be in context of evidence. for attacking conclusion out of context read the post "3 tricks on gmatprep" I posted in gmatclub forum.

we have similar mode to attack when we meet hard strengher and weakener questions. remember testluve advice: figure assumption before going to anserchoices. because weanker and sthengthener attack a far and hard to see assumption, we need to figure out the assumption before realize the strengherner and weakener. knowing to create to hard-to-see assumption you can create the 800 level CR questions because assumption is basement to create most CR questions. Kaplan book say simply but we do not reasize; identifying assumption is key to answering most CR questions.

realizing or making hard-to-see assumption is key to creating and answering most 800 level CR questions.

[GMATMadeEasy]

@duongthang : Thanks. Agreed with what you said. And, that is how ,precisely, I try to do relevant CR questions.

In fact, if you look at my original post i mention, i could see the correct answer choice. This is what will pop-up in one's mind after reading this question.

My question here was because of my inability to understand an answer choice in accordance with the argument after negation. That is to apply the principle in this particular instance. For the answer choice D, i was unable to follow an appropritae direction. Notice how the D is written.

Furthermore, one thing I observed.once you master the technique of Assumption question, you can have fun to play with them.

[Tani]

Actually, at the risk of sounding like a total geek - once you master assumptions the whole test can be fun!

[GMATMadeEasy]

not there yet. Still trying hard. but enjoying the journey nevertheless.