Last visit was: 20 Nov 2025, 04:46 It is currently 20 Nov 2025, 04:46
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
   1   2 
705-805 Level|   Weaken|      
User avatar
fitzpratik
User avatar
Joined: 17 Oct 2016
Last visit: 08 Mar 2021
Posts: 226
Own Kudos:
491
Given Kudos: 49
Location: India
Concentration: General Management, Healthcare
Schools: Owen '22 (I) Boston U '22 (A$) Jones '22 (WL) Kenan-Flagler '22 (WA) Olin '22 (WA$)
GPA: 3.05
WE:Pharmaceuticals (Healthcare/Pharmaceuticals)
Products:
My Reviews
Schools: Owen '22 (I) Boston U '22 (A$) Jones '22 (WL) Kenan-Flagler '22 (WA) Olin '22 (WA$)
Posts: 226
Kudos: 491
Pharmacists recently conducted a study with respect to the reasons the 27 Dec 2018, 05:53
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Debashis Roy
Can somebody explain why B is not stronger than A here in regard to undermining the conclusion?

Thanks in advance
Show more

Pharmacist have found that people who wear contact lenses buy soothing eye drops to manage dry eyes more than people who do not wear contact lenses. Pharmacist assume that wearing contact lenses cause dry eyes.

We want to undermine this conclusion. So What could be other possible explanation?

Possibly, if there is an inherent condition wwhich causes BOTH--> Dry Eyes and poor eysight --> Patients will require both eye drops and contact lenses, in such a case, contact lenses DO NOT CAUSE eye dryness, Still patients will require soothing eye drops.
So A is plausible explanation which can undermine above conclusion.

Now consider B:
Physical exertion causes dry eyes in many people who wear contact lenses.
We dont know, whether people are actually exercising after wearing contacts, so even if the info in B was true, we wont be able to attribute the dryness to contact lenses.

I hope this helps. Experts may provide alternate explanation.
User avatar
fitzpratik
User avatar
Joined: 17 Oct 2016
Last visit: 08 Mar 2021
Posts: 226
Own Kudos:
491
Given Kudos: 49
Location: India
Concentration: General Management, Healthcare
Schools: Owen '22 (I) Boston U '22 (A$) Jones '22 (WL) Kenan-Flagler '22 (WA) Olin '22 (WA$)
GPA: 3.05
WE:Pharmaceuticals (Healthcare/Pharmaceuticals)
Products:
My Reviews
Schools: Owen '22 (I) Boston U '22 (A$) Jones '22 (WL) Kenan-Flagler '22 (WA) Olin '22 (WA$)
Posts: 226
Kudos: 491
Pharmacists recently conducted a study with respect to the reasons the 27 Dec 2018, 05:57
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Wonderwoman31
riteshgupta1
The problem in these questions is to identity what is causing what. If you have to weaken a question like this, here is what you do.

Let say A clause B, typical question will give you an answer choice in which b will cause A and that will be the answer.
similary, if A causes b, then find something where C is clausing B, which clearly refutes the argument.

For example

Contact lens causes dryness.
Ok.
but one of the answer says, no, there is another disease, that causes both. And guess what, whole argument fell apart. This is exactly what happened here.

Hi riteshgupta1

Isn't option A making a logical jump by assuming that only people with weak eyes can wear lenses.
Show more

Actually No,

A says that there is another reason for both the circumstances to coexist. and this reason undermines the conclusion of the pharmacists that contact lenses are causing eye dryness.
User avatar
Wonderwoman31
User avatar
Joined: 21 Apr 2018
Last visit: 22 Apr 2023
Posts: 59
Own Kudos:
44
Given Kudos: 82
Location: India
Schools: Rotman '22 (A$) CBS '22 (D) Wharton '22 (D) INSEAD Jan'21 Intake (A)
GMAT 1: 710 Q50 V35
GMAT 2: 750 Q49 V42
Schools: Rotman '22 (A$) CBS '22 (D) Wharton '22 (D) INSEAD Jan'21 Intake (A)
GMAT 2: 750 Q49 V42
Posts: 59
Kudos: 44
Pharmacists recently conducted a study with respect to the reasons the 27 Dec 2018, 06:23
Kudos
Add Kudos
Bookmarks
Bookmark this Post
fitzpratik
Wonderwoman31
riteshgupta1
The problem in these questions is to identity what is causing what. If you have to weaken a question like this, here is what you do.

Let say A clause B, typical question will give you an answer choice in which b will cause A and that will be the answer.
similary, if A causes b, then find something where C is clausing B, which clearly refutes the argument.

For example

Contact lens causes dryness.
Ok.
but one of the answer says, no, there is another disease, that causes both. And guess what, whole argument fell apart. This is exactly what happened here.

Hi riteshgupta1

Isn't option A making a logical jump by assuming that only people with weak eyes can wear lenses.

Actually No,

A says that there is another reason for both the circumstances to coexist. and this reason undermines the conclusion of the pharmacists that contact lenses are causing eye dryness.
Show more

I can understand when you are saying that both the things are caused by a third factor. But my point is that those two things discussed in option choices and question stimulus are different.

So, when does question states that people with weak eyes wear lenses. What if now people wear lenses only for cosmetic purposes. So, in the given question it is assumed from the reader that he should know that the lenses are worn as a matter of eye defect.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 20 Nov 2025
Posts: 105,414
Own Kudos:
778,485
Given Kudos: 99,987
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,414
Kudos: 778,485
Pharmacists recently conducted a study with respect to the reasons the 08 Mar 2021, 08:45
Kudos
Add Kudos
Bookmarks
Bookmark this Post
huskers
Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?


(A) An inherited condition can cause both weak eyesight and dry eyes.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.

(C) Most people who have dry eyes do not wear contact lenses.

(D) Most people who wear contact lenses do not have dry eyes.

(E) Both weak vision and dry eyes cause headaches.
Show more

Official Explanation



This argument does not consider that an outside factor may cause some people to have both poor vision and dry eyes. Selection (A) provides an outside factor
for both conditions. It is the correct answer. Selection (D) is tempting, but don’t be misled.

Even if most people who wear contact lenses do not have dry eyes, this does not weaken the argument because it is based on the incidence of dry eyes between people who wear contact lenses and those who do not. Secondly, the author does not argue that wearing contact lenses must cause dry eyes, only that it can cause dry eyes.
User avatar
shades28
User avatar
Joined: 05 Sep 2020
Last visit: 22 Jan 2025
Posts: 72
Own Kudos:
30
Given Kudos: 252
Location: India
Schools: ISB '25 (D)
GMAT 1: 600 Q50 V21
GMAT 2: 640 Q47 V32
Schools: ISB '25 (D)
GMAT 2: 640 Q47 V32
Posts: 72
Kudos: 30
Pharmacists recently conducted a study with respect to the reasons the 08 Mar 2021, 11:04
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
huskers
Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?


(A) An inherited condition can cause both weak eyesight and dry eyes.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.

(C) Most people who have dry eyes do not wear contact lenses.

(D) Most people who wear contact lenses do not have dry eyes.

(E) Both weak vision and dry eyes cause headaches.

Official Explanation



This argument does not consider that an outside factor may cause some people to have both poor vision and dry eyes. Selection (A) provides an outside factor
for both conditions. It is the correct answer. Selection (D) is tempting, but don’t be misled.

Even if most people who wear contact lenses do not have dry eyes, this does not weaken the argument because it is based on the incidence of dry eyes between people who wear contact lenses and those who do not. Secondly, the author does not argue that wearing contact lenses must cause dry eyes, only that it can cause dry eyes.
Show more


Hi Bunuel.
Aren't C and D against the premises, warranting that both are wrong answers?
User avatar
Mavisdu1017
User avatar
Joined: 10 Aug 2021
Last visit: 04 Jan 2023
Posts: 360
Own Kudos:
46
Given Kudos: 226
Posts: 360
Kudos: 46
Pharmacists recently conducted a study with respect to the reasons the 24 May 2022, 04:44
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello expert,
The OE of this question is not complete, just addressing D, so need your opinion to B. I think both A and B can weaken the argument with alternative cause, so why B is inferior than A? Thanks in advance.
User avatar
MartyTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,476
Own Kudos:
5,580
Given Kudos: 1,430
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,476
Kudos: 5,580
Pharmacists recently conducted a study with respect to the reasons the 24 May 2022, 05:35
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Mavisdu1017
Hello expert,
The OE of this question is not complete, just addressing D, so need your opinion to B. I think both A and B can weaken the argument with alternative cause, so why B is inferior than A? Thanks in advance.
Show more
Here's the support for the conclusion:

Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses.

So, there is a DIFFERENCE between the frequency of dry eyes in customers who wear contact lenses and and the frequency in customers who do not wear contact lenses, and the conclusion is based on that difference.

Now, here's (B).

(B) Physical exertion causes dry eyes in many people who wear contact lenses.

Notice that (B) doesn't really change what we know. Regardless of what (B) says, it is still the case that dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses, and (B) does not provide AN ALTERNATIVE EXPLANATION FOR THE DIFFERENCE between the frequencies of dry eyes. After all, we have no information indicating that customers who did not wear contact lenses do not ALSO experience dry eyes because of physical exertion. In other words, what (B) says could be THE SAME for people who do not wear contact lenses.

Now, let's consider (A).

(A) An inherited condition can cause both weak eyesight and dry eyes.

Notice that (A) does provide an alternative explanation for the difference between the frequencies of dry eyes. It could be that the inherited condition causes both the wearing of contact lenses and dry eyes of people who wear contact lenses, making these people different in both ways from the people who do not wear contact lenses.

We can see why (B) does not weaken the argument and (A) does.
User avatar
ashutosh_73
User avatar
Joined: 19 Jan 2018
Last visit: 30 Oct 2024
Posts: 234
Own Kudos:
1,642
Given Kudos: 86
Location: India
Posts: 234
Kudos: 1,642
Pharmacists recently conducted a study with respect to the reasons the 03 Aug 2023, 21:44
Kudos
Add Kudos
Bookmarks
Bookmark this Post
huskers
Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?


(A) An inherited condition can cause both weak eyesight and dry eyes.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.

(C) Most people who have dry eyes do not wear contact lenses.

(D) Most people who wear contact lenses do not have dry eyes.

(E) Both weak vision and dry eyes cause headaches.
Show more


Hi KarishmaB ,

Request your help. I am torn between A & D:

Below is my understanding of the options:

Okay, so i know that ''wearing contact lenses(CL) CAN cause contact wearers to have dry eyes(DE)''

(A) An inherited condition can cause both weak eyesight and dry eyes.

There can be thousands of reasons, which can cause Dry eyes, and INHERITED CONDITION is one of them
The stimulus is about contact lenses CAN cause dry eyes. How does the option weaken anyway?
Moreover CAN just explains the possibility. IDK, it seems weird.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.
This one shifts the blame to ''PE'', but ''many'' weakens a bit. But this too seems better than A, which mentions nothing about CL wearers.

(D) Most people who wear contact lenses do not have dry eyes.
I am okay to eliminate this option, as CAN denotes possibility, but given an option between A & D, D seems more plausible.


Thanks :please: :please:
User avatar
KarishmaB
User avatar
Joined: 16 Oct 2010
Last visit: 19 Nov 2025
Posts: 16,267
Own Kudos:
77,002
 [1]
Given Kudos: 482
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,267
Kudos: 77,002
 [1]
Pharmacists recently conducted a study with respect to the reasons the 03 Aug 2023, 22:54
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ashutosh_73
huskers
Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?


(A) An inherited condition can cause both weak eyesight and dry eyes.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.

(C) Most people who have dry eyes do not wear contact lenses.

(D) Most people who wear contact lenses do not have dry eyes.

(E) Both weak vision and dry eyes cause headaches.


Hi KarishmaB ,

Request your help. I am torn between A & D:

Below is my understanding of the options:

Okay, so i know that ''wearing contact lenses(CL) CAN cause contact wearers to have dry eyes(DE)''

(A) An inherited condition can cause both weak eyesight and dry eyes.

There can be thousands of reasons, which can cause Dry eyes, and INHERITED CONDITION is one of them
The stimulus is about contact lenses CAN cause dry eyes. How does the option weaken anyway?
Moreover CAN just explains the possibility. IDK, it seems weird.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.
This one shifts the blame to ''PE'', but ''many'' weakens a bit. But this too seems better than A, which mentions nothing about CL wearers.

(D) Most people who wear contact lenses do not have dry eyes.
I am okay to eliminate this option, as CAN denotes possibility, but given an option between A & D, D seems more plausible.


Thanks :please: :please:
Show more


When a conclusion says "A causes B," we can weaken it by saying "B causes A" or "C causes both A and B."

Don't worry about the "CAN" used in option (A). It does make us doubt our conclusion and that's all we want. We don't need to PROVE the conclusion. We just have to say that it is possible that A doesn't cause B. Hence option (A) works. It says "an inherited condition can cause both" and that is why they appear together often. Not because one causes the other.

Option (D) slides into Quant category.


Say total 50 people have dry eyes and they buy drops - 10 non contact lens wearers and 40 contact lens wearers.
So pharmacists concluded that contact lenses can cause dry eyes.

(D) Most people who wear contact lenses do not have dry eyes.

Say 200 people wear contact lenses. If only 40 have dry eyes, then most contact lens wearers do not have dry eyes.

But it doesn't weaken our conclusion that contact lenses can cause dry eyes. Perhaps they did in the 40 lens wearers. After all, in the rest of the public, only 10 people have dry eyes.

That is why option (D) doesn't weaken our conclusion.

I discussed this question in a webinar. Check out the video here: https://youtu.be/XCBp62o70Eg
User avatar
Kartikeya40
User avatar
Joined: 29 Jun 2023
Last visit: 29 Apr 2024
Posts: 15
Own Kudos:
1
Given Kudos: 16
Location: India
Posts: 15
Kudos: 1
Pharmacists recently conducted a study with respect to the reasons the 10 Oct 2023, 11:05
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Option (A) doesn't explain why dry eyes would occur only for people with contact lenses but not for people who use glasses perhaps
User avatar
MartyMurray
User avatar
Joined: 11 Aug 2023
Last visit: 19 Nov 2025
Posts: 1,632
Own Kudos:
6,128
Given Kudos: 173
GMAT 1: 800 Q51 V51
Expert
Expert reply
GMAT 1: 800 Q51 V51
Posts: 1,632
Kudos: 6,128
Pharmacists recently conducted a study with respect to the reasons the 10 Oct 2023, 11:39
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Kartikeya40
Option (A) doesn't explain why dry eyes would occur only for people with contact lenses but not for people who use glasses perhaps
Show more
Notice that the passage doesn't say that people who wear glasses don't experience dry eyes as frequently as people who wear contact lenses. In fact, the passage doesn't say that people who don't wear contact lenses don't experience dry eyes sometimes.

Rather the support for the conclusion is simply "Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses."

So, could be both that people who wear contact lenses experience dry eyes more frequently than all the people who do not wear contact lenses and that people who use glasses experience dry eyes more frequently than all the people who do not use glasses.

So, there's no issue related to people who wear glasses also experiencing dry eyes.
User avatar
KarishmaB
User avatar
Joined: 16 Oct 2010
Last visit: 19 Nov 2025
Posts: 16,267
Own Kudos:
77,002
Given Kudos: 482
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,267
Kudos: 77,002
Pharmacists recently conducted a study with respect to the reasons the 11 Oct 2023, 00:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Kartikeya40
Option (A) doesn't explain why dry eyes would occur only for people with contact lenses but not for people who use glasses perhaps
Show more

Comparison is between 'Contacts' vs 'Others'.
'Others' includes people with glasses and people with good eyesight.

People with 'contacts' experienced dry eyes more frequently than 'others (glasses + good eyes)'.

(A) An inherited condition can cause both weak eyesight and dry eyes.

This means people with contacts and people with glasses both are likely to have dry eyes more frequently.
The proportion of dry eyes in 'contacts' group will be higher because everyone has weak eyesight there.
The proportion of dry eyes in 'others' group will be lower because only a fraction has weak eyesight there.

Hence (A) works.
User avatar
MohdZaidKhan
User avatar
Joined: 23 Jun 2024
Last visit: 23 Sep 2025
Posts: 26
Own Kudos:
1
Given Kudos: 64
Location: India
Schools: Stanford '27 NYU Stern
Schools: Stanford '27 NYU Stern
Posts: 26
Kudos: 1
Pharmacists recently conducted a study with respect to the reasons the 21 Oct 2024, 23:06
Kudos
Add Kudos
Bookmarks
Bookmark this Post
huskers
Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?


(A) An inherited condition can cause both weak eyesight and dry eyes.

(B) Physical exertion causes dry eyes in many people who wear contact lenses.

(C) Most people who have dry eyes do not wear contact lenses.

(D) Most people who wear contact lenses do not have dry eyes.

(E) Both weak vision and dry eyes cause headaches.
Show more

Somebody please clear my doubt -
Conclusion -Contact lenses(C) can cause dry eyes(D) .
A- I can cause both C and D .
C- I understood that the poeple not wearing contact lenses could be very very large in numbers than people wearing C .causing most people having D dont have C . which is not weakening the conclusion
D- this fact can invalidate the conclusion I guess. Reason being most (more than 50%) is fulfilling the sufficient condition but the outcome is not happening.
E-irrelevant .
   1   2 
Moderators:
GMATNinja
GMAT Club Verbal Expert
7443 posts
GMATNinjaTwo
GMAT Club Verbal Expert
231 posts
miag
189 posts