GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 Feb 2019, 17:17

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Prep Hour

February 20, 2019

February 20, 2019

08:00 PM EST

09:00 PM EST

Strategies and techniques for approaching featured GMAT topics. Wednesday, February 20th at 8 PM EST

February 21, 2019

February 21, 2019

10:00 PM PST

11:00 PM PST

Kick off your 2019 GMAT prep with a free 7-day boot camp that includes free online lessons, webinars, and a full GMAT course access. Limited for the first 99 registrants! Feb. 21st until the 27th.

# V21-01

Author Message
TAGS:

### Hide Tags

Current Student
Joined: 19 Mar 2012
Posts: 4350
Location: India
GMAT 1: 760 Q50 V42
GPA: 3.8
WE: Marketing (Non-Profit and Government)

### Show Tags

13 Feb 2018, 09:42
00:00

Difficulty:

55% (hard)

Question Stats:

45% (01:17) correct 55% (01:33) wrong based on 20 sessions

### HideShow timer Statistics

Aldolase is a protein found in the brain. In an experiment, subjects who consistently chose sweetened drinks when offered a choice between salty and sweetened drinks were found, on average, to have significantly higher concentrations of Aldolase in their brains than subjects who consistently chose salty drinks over sweetened drinks. Thus, an increase in the level of Aldolase in the brain is likely to cause an increase in cravings for sweetened drinks. Which one of the following, if true, most supports the argument?

A. Craving sweetened drinks does not invariably result in a subject’s choosing those drinks over salty drinks.
B. The brains of the subjects who consistently chose to drink sweetened drinks did not contain significantly more sugar than the brains of subjects that consistently chose salty drinks.
C. The chemical components of Aldolase are present in sweetened drinks.
D. The subjects that preferred sweetened drinks had higher concentrations of Aldolase in their brains before they were offered sweetened drinks.
E. In a study of subjects who drank one sweetened drink per day for an entire year, the concentrations of Aldolase in the brains of most subjects gradually increased over the course of the year.

_________________
Current Student
Joined: 19 Mar 2012
Posts: 4350
Location: India
GMAT 1: 760 Q50 V42
GPA: 3.8
WE: Marketing (Non-Profit and Government)

### Show Tags

13 Feb 2018, 09:42
1
Official Solution:

Aldolase is a protein found in the brain. In an experiment, subjects who consistently chose sweetened drinks when offered a choice between salty and sweetened drinks were found, on average, to have significantly higher concentrations of Aldolase in their brains than subjects who consistently chose salty drinks over sweetened drinks. Thus, an increase in the level of Aldolase in the brain is likely to cause an increase in cravings for sweetened drinks. Which one of the following, if true, most supports the argument?

A. Craving sweetened drinks does not invariably result in a subject’s choosing those drinks over salty drinks.
B. The brains of the subjects who consistently chose to drink sweetened drinks did not contain significantly more sugar than the brains of subjects that consistently chose salty drinks.
C. The chemical components of Aldolase are present in sweetened drinks.
D. The subjects that preferred sweetened drinks had higher concentrations of Aldolase in their brains before they were offered sweetened drinks.
E. In a study of subjects who drank one sweetened drink per day for an entire year, the concentrations of Aldolase in the brains of most subjects gradually increased over the course of the year.

This is a classic correlation vs. causation CR question.

And as always, I like to start with a nice, clear restatement of the conclusion: Thus, an increase in the level of Aldolase in the brain is likely to cause an increase in cravings for sweetened drinks.

This is strong, clear causal language: Aldolase causes the increase in cravings for sweetened drinks. And what's the reasoning given in the passage itself? Really, it's just one sentence that leads to the conclusion:In an experiment, subjects who consistently chose sweetened drinks when offered a choice between salty and sweetened drinks were found, on average, to have significantly higher concentrations of Aldolase in their brains than subjects who consistently chose salty drinks over sweetened drinks.The author assumes that Aldolase is the cause of the cravings for sweetened drinks, but as is often the case in correlation vs. causation questions, we might wonder if the direction of causality could also be reversed.

The author says that Aldolase causes the cravings, but why couldn't the consumption of sweetened drinks lead to higher concentrations of Aldolase in the brain instead? The question is just asking us to strengthen the conclusion ("an increase in the level of Aldolase in the brain is likely to cause an increase in cravings for sweetened drinks.") One way to strengthen the conclusion might be to eliminate the possibility of a "causal reversal": that the sweetened drinks cause the increase in Aldolase in the brain, instead of Aldolase causing an increase in cravings for sweetened drinks. Also notice that we do not need a statement that PROVES that the conclusion is true; rather, we need a statement that SUPPORTS the argument.

(A) Craving sweetened drinks does not invariably result in a subject’s choosing those drinks over salty drinks.

Statement (A) is tempting at first! At first glance, it seems it seems to eliminate the "causal reversal" we discussed above. The trouble is, (A) only addresses the link between craving sweetened drinks and choosing those drinks; it does nothing to link Aldolase to the cravings or the consumption of sweetened drinks. And as we'll see in a moment,

(D) is a much stronger answer.

(B) The brains of the subjects who consistently chose to drink sweetened drinks did not contain significantly more sugar than the brains of subjects that consistently chose salty drinks.The argument discusses the concentration of Aldolase in the brains of subjects, but the amount of sugar in subjects' brains is irrelevant to the argument. We can eliminate (B).

(C) The chemical components of Aldolase are present in sweetened drinks.The argument claims that Aldolase in the brain causes subjects to crave sweetened drinks. Whether Aldolase is present in the drinks themselves is irrelevant to the argument. And even if we (improperly!) assume that drinking "the chemical components of Aldolase" leads to increased Aldolase in the brain, then this would work against the argument, since it would suggest that drinking sweetened drinks causes higher levels of Aldolase in the brain. Either way, (C) is gone.

(D) The subjects that preferred sweetened drinks had higher concentrations of Aldolase in their brains before they were offered sweetened drinks.The answer strengthens the argument by eliminating the possibility that the stated causal relationship is reversed: if the subjects had higher concentrations of Aldolase prior to taking the sweetened drinks, then the sweetened drinks cannot be the cause of the higher concentration of Aldolase. This does not PROVE that the conclusion is true, but it certainly supports the argument.

(E) In a study of subjects who drank one sweetened drink per day for an entire year, the concentrations of Aldolase in the brains of most subjects gradually increased over the course of the year.(E) hurts the argument by suggesting that the causal relationship in the conclusion is reversed: if (E) is true, then drinking sweetened drinks would increase Aldolase levels in the brain, instead of the other way around.So (D) is our answer.

_________________
Study Buddy Forum Moderator
Joined: 04 Sep 2016
Posts: 1299
Location: India
WE: Engineering (Other)

### Show Tags

09 Mar 2018, 06:26
GMATNinja GMATNinjaTwo VeritasPrepKarishma generis

Conclusion:Causal one. an increase in the level of Aldolase in the brain is likely to cause an increase in cravings for sweetened drinks
where cause:an increase in the level of Aldolase in the brain
effect: an increase in cravings for sweetened drinks

How does author arrive here:
Quote:
In an experiment, subjects who consistentlychose sweetened drinks when offered a choice between salty and sweetened drinks were found, on average, to have significantly higher concentrations of Aldolase in their brains than subjects who consistently chose salty drinks over sweetened drinks

Say a person X chose sweetened drink multiple times and a person Y who took salty drink multiple times,
then the level of concentrations of Aldolase is found higher in former than latter.

But first sentence of argument says: Aldolase is a protein found in brain.

How can multiple intakes of a drink / preference of one over another prompt author to arrive at such a conclusion?

Is not (D) an assumption as well?

Let me present two version of negations:

1.The subjects that preferred sweetened drinks did not have higher concentrations of Aldolase in their brains before they were offered sweetened drinks.
(How does this affect my conclusion?)

2.The subjects that preferred sweetened drinks had higher concentrations of Aldolase in their brains after they were offered sweetened drinks.
I feel second version of negation reverses the causal relationship and hence is it apt to say that conclusion now is invalid?
_________________

It's the journey that brings us happiness not the destination.

GMAT Club Verbal Expert
Joined: 20 Nov 2016
Posts: 260

### Show Tags

13 Mar 2018, 10:03
GMATNinja GMATNinjaTwo VeritasPrepKarishma generis

Conclusion:Causal one. an increase in the level of Aldolase in the brain is likely to cause an increase in cravings for sweetened drinks
where cause:an increase in the level of Aldolase in the brain
effect: an increase in cravings for sweetened drinks

How does author arrive here:
Quote:
In an experiment, subjects who consistentlychose sweetened drinks when offered a choice between salty and sweetened drinks were found, on average, to have significantly higher concentrations of Aldolase in their brains than subjects who consistently chose salty drinks over sweetened drinks

Say a person X chose sweetened drink multiple times and a person Y who took salty drink multiple times,
then the level of concentrations of Aldolase is found higher in former than latter.

But first sentence of argument says: Aldolase is a protein found in brain.

How can multiple intakes of a drink / preference of one over another prompt author to arrive at such a conclusion?

Is not (D) an assumption as well?

Let me present two version of negations:

1.The subjects that preferred sweetened drinks did not have higher concentrations of Aldolase in their brains before they were offered sweetened drinks.
(How does this affect my conclusion?)

2.The subjects that preferred sweetened drinks had higher concentrations of Aldolase in their brains after they were offered sweetened drinks.
I feel second version of negation reverses the causal relationship and hence is it apt to say that conclusion now is invalid?

adkikani, your first negation version is correct. Just because (D) is not true, does not necessarily mean that your second negation version is true. In other words, just because they did NOT have higher concentrations before, does not necessarily mean that they had higher concentrations after.

Check out the official explanation for (D) in this QOTD post. If you still have questions, please post them to that thread.

Thank you!
_________________
Re: V21-01   [#permalink] 13 Mar 2018, 10:03
Display posts from previous: Sort by

# V21-01

Moderators: chetan2u, Bunuel

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.