It is currently 17 Oct 2017, 17:39

### 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 June
Open Detailed Calendar

# Manufacturers of motor oil for car engines have found

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Director
Status: 1,750 Q's attempted and counting
Affiliations: University of Florida
Joined: 09 Jul 2013
Posts: 514

Kudos [?]: 982 [0], given: 630

Location: United States (FL)
Schools: UFL (A)
GMAT 1: 600 Q45 V29
GMAT 2: 590 Q35 V35
GMAT 3: 570 Q42 V28
GMAT 4: 610 Q44 V30
GPA: 3.45
WE: Accounting (Accounting)
Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

23 Nov 2013, 14:24
1
This post was
BOOKMARKED
00:00

Difficulty:

35% (medium)

Question Stats:

65% (01:17) correct 35% (01:46) wrong based on 411 sessions

### HideShow timer Statistics

Manufacturers of motor oil for car engines have found through research that motor oil slowly loses lubrication effectiveness after the car is driven for certain distances. On average, the motor oil is only fifty percent as effective after 3,000 miles of driving as it is the first day it is put into the car. For that reason, people should replace their motor oil every 3,000 miles.

Which of the following, if true, would most weaken the conclusion above?

(A) The research indicates that the oil loses effectiveness because it becomes dirty.
(B) The researchers found that there was not a significant difference in the effectiveness of motor oil in cars that reached 3,000 miles quickly versus those that took a long time to reach 3,000 miles.
(C) The researchers found that cars with motor oil at fifty percent effectiveness showed no more signs of damage or wear than those with fresh motor oil.
(D) The researchers were paid by the manufacturers of motor oil, who have a vested interest in selling more motor oil.
(E) Both synthetic and non-synthetic motor oils experience similar losses in motor oil effectiveness after 3,000 miles of driving.

OE to follow
[Reveal] Spoiler: OA

Kudos [?]: 982 [0], given: 630

Director
Status: 1,750 Q's attempted and counting
Affiliations: University of Florida
Joined: 09 Jul 2013
Posts: 514

Kudos [?]: 982 [0], given: 630

Location: United States (FL)
Schools: UFL (A)
GMAT 1: 600 Q45 V29
GMAT 2: 590 Q35 V35
GMAT 3: 570 Q42 V28
GMAT 4: 610 Q44 V30
GPA: 3.45
WE: Accounting (Accounting)
Re: Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

28 Nov 2013, 21:47

Official Explanation

Answer C - In this argument, the conclusion is that people should change their motor oil every 3,000 miles. The conclusion is based on the fact that motor oil loses half of its effectiveness after being driven that distance. The central assumption here is that the loss of effectiveness is indeed a valid reason for changing the motor oil. Choice (C) challenges this assumption by saying that cars with motor oil at fifty percent effectiveness do not have any ill effects. Thus, choice (C) is the correct answer.

Choices (A), (B), and (E) are all out of scope. The fact that oil loses effectiveness because it becomes dirty does not weaken the conclusion. It also does not matter that cars that reach 3,000 miles at different rates experience similar declines in motor oil effectiveness; it also does not matter that the same is true of cars with different types of motor oil.

Choice (D) may be tempting, but is ultimately irrelevant. We may want to gravitate to a choice like (D) that questions the motives for the research, however we never want to challenge the evidence itself in a weaken question – only the central assumption. Even though the research was conducted under the supervision of motor oil companies, this does not alone weaken the conclusion that motor oil should be changed every 3,000 miles.

Kudos [?]: 982 [0], given: 630

Intern
Joined: 11 Nov 2013
Posts: 22

Kudos [?]: 1 [0], given: 0

Re: Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

28 Nov 2013, 23:27
[quote="avohden"]Manufacturers of motor oil for car engines have found through research that motor oil slowly loses lubrication effectiveness after the car is driven for certain distances. On average, the motor oil is only fifty percent as effective after 3,000 miles of driving as it is the first day it is put into the car. For that reason, people should replace their motor oil every 3,000 miles.

Which of the following, if true, would most weaken the conclusion above?

(A) The research indicates that the oil loses effectiveness because it becomes dirty.
(B) The researchers found that there was not a significant difference in the effectiveness of motor oil in cars that reached 3,000 miles quickly versus those that took a long time to reach 3,000 miles.
(C) The researchers found that cars with motor oil at fifty percent effectiveness showed no more signs of damage or wear than those with fresh motor oil.
(D) The researchers were paid by the manufacturers of motor oil, who have a vested interest in selling more motor oil.
(E) Both synthetic and non-synthetic motor oils experience similar losses in motor oil effectiveness after 3,000 miles of driving.

Hello Dear,
the effectiveness of 50 percent is after every 3000 miles ia right think about engine oil..but if we can't change it then engine power is slightly fall down after some time..
I know option C is right but it is not applicable for every engine oil..

Kudos [?]: 1 [0], given: 0

Manager
Joined: 11 Sep 2016
Posts: 56

Kudos [?]: 14 [0], given: 120

Location: Azerbaijan
Concentration: Finance, General Management
GMAT 1: 570 Q44 V27
GPA: 3.11
WE: Other (Consulting)
Re: Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

28 Nov 2016, 05:09
surajkumar00116 wrote:
avohden wrote:
Manufacturers of motor oil for car engines have found through research that motor oil slowly loses lubrication effectiveness after the car is driven for certain distances. On average, the motor oil is only fifty percent as effective after 3,000 miles of driving as it is the first day it is put into the car. For that reason, people should replace their motor oil every 3,000 miles.

Which of the following, if true, would most weaken the conclusion above?

(A) The research indicates that the oil loses effectiveness because it becomes dirty.
(B) The researchers found that there was not a significant difference in the effectiveness of motor oil in cars that reached 3,000 miles quickly versus those that took a long time to reach 3,000 miles.
(C) The researchers found that cars with motor oil at fifty percent effectiveness showed no more signs of damage or wear than those with fresh motor oil.
(D) The researchers were paid by the manufacturers of motor oil, who have a vested interest in selling more motor oil.
(E) Both synthetic and non-synthetic motor oils experience similar losses in motor oil effectiveness after 3,000 miles of driving.

Hello Dear,
the effectiveness of 50 percent is after every 3000 miles ia right think about engine oil..but if we can't change it then engine power is slightly fall down after some time..
I know option C is right but it is not applicable for every engine oil..

It shouldn't be applicable to all types of engines, because premise states "On average, the motor oil is only fifty percent as effective after 3,000 miles of driving as it is the first day it is put into the car"
_________________

Press +1 Kudos if my post helped you a little and help me to ulcock the tests Wish you all success

Kudos [?]: 14 [0], given: 120

Manager
Joined: 27 Aug 2016
Posts: 95

Kudos [?]: 4 [0], given: 149

Location: India
Schools: HEC Montreal '21
GMAT 1: 670 Q47 V37
GPA: 3
WE: Engineering (Energy and Utilities)
Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

20 Dec 2016, 11:57
avohden wrote:

Official Explanation

Answer C - In this argument, the conclusion is that people should change their motor oil every 3,000 miles. The conclusion is based on the fact that motor oil loses half of its effectiveness after being driven that distance. The central assumption here is that the loss of effectiveness is indeed a valid reason for changing the motor oil. Choice (C) challenges this assumption by saying that cars with motor oil at fifty percent effectiveness do not have any ill effects. Thus, choice (C) is the correct answer.

Choices (A), (B), and (E) are all out of scope. The fact that oil loses effectiveness because it becomes dirty does not weaken the conclusion. It also does not matter that cars that reach 3,000 miles at different rates experience similar declines in motor oil effectiveness; it also does not matter that the same is true of cars with different types of motor oil.

Choice (D) may be tempting, but is ultimately irrelevant. We may want to gravitate to a choice like (D) that questions the motives for the research, however we never want to challenge the evidence itself in a weaken question – only the central assumption. Even though the research was conducted under the supervision of motor oil companies, this does not alone weaken the conclusion that motor oil should be changed every 3,000 miles.
ot.

Please explain further why not D? A flawed research with vested interests directly strikes out the first statement. Had there been an honest research probably the result would have been that there was no loss of lubrication.

Kudos [?]: 4 [0], given: 149

Manager
Joined: 02 Nov 2013
Posts: 97

Kudos [?]: 9 [0], given: 10

Location: India
Re: Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

22 Dec 2016, 09:26
Here is my explanation for the argument,
(A) The research indicates that the oil loses effectiveness because it becomes dirty. ----- There is no information about oil getting dirty in the argument.
(B) The researchers found that there was not a significant difference in the effectiveness of motor oil in cars that reached 3,000 miles quickly versus those that took a long time to reach 3,000 miles. ----- time to reach the 3000 miles does not effect the performance of the oil... Not correct
(C) The researchers found that cars with motor oil at fifty percent effectiveness showed no more signs of damage or wear than those with fresh motor oil. ----- Correct, Proves that even after fifty percent effectiveness shows signs equivalent to fresh motor oil..
(D) The researchers were paid by the manufacturers of motor oil, who have a vested interest in selling more motor oil.---
(E) Both synthetic and non-synthetic motor oils experience similar losses in motor oil effectiveness after 3,000 miles of driving.---- categorization of motor oil in synthetic and non synthetic is not available in the argument.

Kudos [?]: 9 [0], given: 10

Manager
Joined: 04 Jun 2015
Posts: 86

Kudos [?]: 53 [0], given: 2

Re: Manufacturers of motor oil for car engines have found [#permalink]

### Show Tags

27 Dec 2016, 01:29
avohden wrote:
Manufacturers of motor oil for car engines have found through research that motor oil slowly loses lubrication effectiveness after the car is driven for certain distances. On average, the motor oil is only fifty percent as effective after 3,000 miles of driving as it is the first day it is put into the car. For that reason, people should replace their motor oil every 3,000 miles.

Which of the following, if true, would most weaken the conclusion above?

(A) The research indicates that the oil loses effectiveness because it becomes dirty.
(B) The researchers found that there was not a significant difference in the effectiveness of motor oil in cars that reached 3,000 miles quickly versus those that took a long time to reach 3,000 miles.
(C) The researchers found that cars with motor oil at fifty percent effectiveness showed no more signs of damage or wear than those with fresh motor oil.
(D) The researchers were paid by the manufacturers of motor oil, who have a vested interest in selling more motor oil.
(E) Both synthetic and non-synthetic motor oils experience similar losses in motor oil effectiveness after 3,000 miles of driving.

I was stuck between B and C. But ultimately chose B.
I reasoned B as the right one because B says there is no significant difference in effectiveness of the oil that reached 3000 miles (the claimed time to change the oil) vs. oil that took time to reach 3000 miles (the oil present from the moment it was put in). So if there is no significant difference in effectiveness then it doesn't make any sense changing the oil after 3000 miles (since the car is claimed to run normally when the oil is initially put in).

_________________

Sortem sternit fortem!

Kudos [?]: 53 [0], given: 2

Re: Manufacturers of motor oil for car engines have found   [#permalink] 27 Dec 2016, 01:29
Display posts from previous: Sort by

# Manufacturers of motor oil for car engines have found

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.