Official Explanation

Despite the relentless pursuit of fitness portrayed by the media, the population of the nation is, on average, plumper than was the population 30 years ago. By 2008, the average adult is 11 pounds heavier than was the average adult in 1978.

Which of the following is an assumption underlying the argument above regarding today's average adult?

(A) Today's average adult is not substantially overweight.

Incorrect.

To solve this Assumption question, first break down the argument. The second sentence includes hard statistical data so it must be the premise. As for the first sentence, we can only see that it is a conclusion because it relies on the second. Tricky one!

Now ask yourself: the author believes the average adult today is plumper (rounder or fatter) than was the average adult 30 years ago, based on their weight. But what is the missing link? What unfounded connection (assumption) does the author make?

The fact that today's average adult is not substantially overweight is irrelevant to the comparison between the average adult weight today and 30 years ago. Therefore, this is not a necessary assumption to reach the conclusion that today's average adult is plumper.

Did you know the meaning of the word plumper when you answered the question?

Plumpness is not just about weighing more. It is about the ratio of weight to height. To conclude that today's average adult is plumper, the author had to take into consideration both weight and height (a 6 foot tall man weighing 200 pounds in not plumper than a 5 foot tall man weighing 189 pounds - he's just bigger!).

(B) Today's average adult is trying to lose weight.

Incorrect.

This answer choice presents a new premise about today's average adult. It is irrelevant whether this new data supports the conclusion; what you are looking for is the assumption, which should explain how the author drew the conclusion based on the existing premise.

(C) Today's average adult eats healthier food than did the average adult of the past.

Incorrect.

If the author assumed today's average adult eats healthier food, why would the author draw the conclusion that today's average adult is plumper? This answer choice contradicts the conclusion.

(D) Today's average adult is not older than was the average adult of the past.

Incorrect.

This answer choice presents a new premise about today's average adult. It is irrelevant whether this new data supports the conclusion; what you are looking for is the assumption, which should explain how the author drew the conclusion based on the existing premise.

(E) Today's average adult is not significantly taller than was the average adult of the past.

Plumpness is not just about weighing more. It is about the ratio of weight to height. To conclude that today's average adult is plumper, the author had to take into consideration both weight and height (a 6 foot tall man weighing 200 pounds is not plumper than a 5 foot tall man weighing 189 pounds - he's just bigger!). This answer choice presents a necessary assumption linking the premise to the conclusion, because without assuming that the heights are similar, the conclusion that today's average adult is plumper than his counterpart 30 years ago is weakened.

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Despite the relentless pursuit of fitness portrayed by the media, the population of the nation is, on average, plumper than was the population 30 years ago. By 2008, the average adult is 11 pounds heavier than was the average adult in 1978.

Which of the following is an assumption underlying the argument above regarding today's average adult?

(A) Today's average adult is not substantially overweight. Incorrect

it against argument

(B) Today's average adult is trying to lose weight. Incorrect

it doesnt mean they are heavier than previous

(C) Today's average adult eats healthier food than did the average adult of the past. Incorrect

cant say healthier food is the cause for heavier weight

(D) Today's average adult is not older than was the average adult of the past. Incorrect

irrelevant

(E) Today's average adult is not significantly taller than was the average adult of the past. Correct

so, 11 pounds heavier because they are plumper

Conclusion: The population of the nation is, on average, plumper than was the population 30 years ago. By 2008, the average adult is 11 pounds heavier than was the average adult in 1978.

Pre-thinking: Current youth is plumper than 30 years ago and current youth is heavier too. It means, there is no another reason for current youth to be heavier.

Which of the following is an assumption underlying the argument above regarding today's average adult?

(A) Today's average adult is not substantially overweight. -> We are comparing 30 years back data. Incorrect.
(B) Today's average adult is trying to lose weight. -> Irrelevant.
(C) Today's average adult eats healthier food than did the average adult of the past. -> Irrelevant.
(D) Today's average adult is not older than was the average adult of the past. -> Age is not linked with weight.
(E) Today's average adult is not significantly taller than was the average adult of the past. -> So, It is negating another option of taller adults. Let's keep it.

So, I think E.

imo E
Despite the relentless pursuit of fitness portrayed by the media, the population of the nation is, on average, plumper than was the population 30 years ago. By 2008, the average adult is 11 pounds heavier than was the average adult in 1978.

Which of the following is an assumption underlying the argument above regarding today's average adult?


Conclusion: The population of the nation is, on average, plumper than was the population 30 years ago.
Given
By 2008, the average adult is 11 pounds heavier than was the average adult in 1978.

We can assume that
the increase in 11 pounds is not due to any another reason such as muscle building or something else

Only option E .. echos in the same line

(A) Today's average adult is not substantially overweight.
(B) Today's average adult is trying to lose weight.
(C) Today's average adult eats healthier food than did the average adult of the past.
(D) Today's average adult is not older than was the average adult of the past.
(E) Today's average adult is not significantly taller than was the average adult of the past.

(A) Today's average adult is not substantially overweight
- our premise says the opposite. Incorrect

(B) Today's average adult is trying to lose weight.
- No mention of such text. Incorrect

(C) Today's average adult eats healthier food than did the average adult of the past.
- No mention of such information. Incorrect

(D) Today's average adult is not older than was the average adult of the past.
- same as (B) and (C), Incorrect

(E) Today's average adult is not significantly taller than was the average adult of the past.
- Correctly negates the information. Correct

In my opinion, though it doesn't matter, without knowing what is plumpiness, this question can't be answered.
Negating Choice B can also destroy the conclusion, right? If today's average adult is not trying to lose weight, then he'll be heavier than the ones before (in '78), right?
Choice E can only be correct if one knows what plumpiness is.

Posted from my mobile device

I sort of agree with what shades28 has said. Can any expert help us out ? AndrewN, carouselambra, GMATNinja.

Hello, kntombat. To be honest, I think any of a number of assumptions could be true in this one, but, of course, you have to go by what you see on the screen. The part about (B) that can be enticing is that trying to lose weight can be associated with the relentless pursuit of fitness from the first line of the passage. But I had reservations, perhaps because the goal of fitness may not necessarily be weight loss. Bodybuilders, for instance, seek to gain weight by putting on muscle mass. While such weight gain would figure into a larger—heavier—average adult today than the average adult of thirty years ago, when weightlifting was not as widespread, I cannot say that bodybuilders would be considered plump, what I think of as a little doughy from the waist on up.

Choice (E) uses probably the most commonly employed over-qualifying word that appears in correct answers to Verbal GMAT™ questions: significantly. A significantly taller person would logically be one with a potential to pack on more weight. But plumpness? That can enter the picture regardless of height, and we do not know what significantly may mean—a foot? six inches? four?

In short, I chose (E) as a safer answer, but I was not thinking about a weight-to-height ratio, nor do I think the GMAT™ would require such specialized knowledge of a test-taker (and I am next to positive that the judgmental word plump or its variants would not appear on the exam). I would suggest treating this question as a curio, nothing more.

Thank you for thinking to ask.

- Andrew
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A good thing to be on the lookout for (especially in Find the Assumption or Weaken the Argument question types) are any subtle shifts in language from the Facts to the Conclusion.

The author states in the conclusion that the average person is “plumper.”

However, the evidence used is absolute numbers regarding the difference in “pounds.”

Focusing on the Gap between what constitutes “plumpness” and the facts about differences in the number of pounds will allow you to see what the author must be assuming.

The author needs to assume that the fact about the change in number of pounds is relevant to the concept of “plumpness”. (I love saying that word)

Answer E, if true, would hurt the logic of the argument and the claim that the population, on average, is plumper. After all, a person who is 6 foot 2 , 220 lbs is a lot less “plump” than a person who is 5 foot 5, 210 lbs.


Edit: and I’m in complete agreement with AndrewN above me.

The concept of what constitutes “plump” is not something I can ever see showing up on an official question.


Plump.....plump.
Posted from my mobile device