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

 It is currently 16 Oct 2019, 00:27

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

John and Fawn, each drinking at a constant pace, can finish

Author Message
TAGS:

Hide Tags

Manager
Joined: 25 Nov 2011
Posts: 149
Location: India
Concentration: Technology, General Management
GPA: 3.95
WE: Information Technology (Computer Software)
John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

17 Feb 2012, 19:53
8
00:00

Difficulty:

75% (hard)

Question Stats:

56% (01:58) correct 44% (02:08) wrong based on 374 sessions

HideShow timer Statistics

John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

This is actually from MGMAT flash cards. Looked interesting and hence I posted after modifying it a bit (I added a new statement).

_________________
-------------------------
-Aravind Chembeti
Math Expert
Joined: 02 Sep 2009
Posts: 58369
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

17 Feb 2012, 21:55
4
3
Chembeti wrote:
John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

This is actually from MGMAT flash cards. Looked interesting and hence I posted after modifying it a bit (I added a new statement).

John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

Given: 1/J + 1/F = 1/12

(1) The average time it would take both to finish independently is 30 hours --> J+F=60. Now, since we don't know which one drinks faster then even if we substitute F with 60-J (1/J + 1/(60-J) = 1/12) we must get two different answers for J and F: J<F and J>F. Not sufficient.

(2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case --> F=J-10 --> 1/J + 1/(J-10) = 1/12 --> J=4 (not a valid solution as F in this case is negative) and J=30 (F=20). Sufficient.

Now, technically the answer should be B, as Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

But even though the formal answer to the question is B, this is not a realistic GMAT question, as: on the GMAT, two data sufficiency statements always provide TRUE information and these statements never contradict each other. In our question, from (2) we have that the average time is (30+20)/2=25 and (1) states that it's 30, so the statements clearly contradict each other.

In order it to be a realistic GMAT question (1) should read: The average time it would take John to finish the case drinking alone and Fawn to finish the case drinking alone is 25 hours. In this case for (1) we'll have: 1/J + 1/(50-J) = 1/12 --> J=30 (so F=20 --> J>F) or J=20 (so F=30 --> J<F). Statements don't contradict and (1) is still insufficient.

Hope it's clear.
_________________
General Discussion
Manager
Status: May The Force Be With Me (D-DAY 15 May 2012)
Joined: 06 Jan 2012
Posts: 198
Location: India
Concentration: General Management, Entrepreneurship
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

17 Feb 2012, 21:11
Hi,

I think the OA is incorrect. I think it should be D

Statement 1 : Each takes 30 hours to finish the case independently => John can finish a case in 30 hours hence sufficient
Statement 2 : J = F+10

1/J + 1/F = 1/12

1/(F+10) + 1/F = 1/12

Solving the quadratic equation we get F = 20 / F =-6. Work time problem hence -6 is eliminated

Hence we can find J

Hence Statement 2 is sufficient

Hence D
_________________
Giving +1 kudos is a better way of saying 'Thank You'.
Manager
Joined: 31 Jan 2012
Posts: 69
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

17 Feb 2012, 21:20
Statement 1 can't be correct because you don't know who out of the 2 is the faster drinker... John could drink faster than his friend or vice versa. Also you definition of average is wrong... Average mean A+B/2. A and B does not have to be the same. It could take John 50 mins to finish and Fawn 10 mins The average would still be 30
Manager
Status: Retaking next month
Affiliations: None
Joined: 05 Mar 2011
Posts: 123
Location: India
Concentration: Marketing, Entrepreneurship
GMAT 1: 570 Q42 V27
GPA: 3.01
WE: Sales (Manufacturing)
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

17 Feb 2012, 21:35
kys123 wrote:
Statement 1 can't be correct because you don't know who out of the 2 is the faster drinker... John could drink faster than his friend or vice versa. Also you definition of average is wrong... Average mean A+B/2. A and B does not have to be the same. It could take John 50 mins to finish and Fawn 10 mins The average would still be 30

Faster drinker !!!! where does that come from???

St 1 Clearly states that "The average time it would take both to finish independently is 30 hours".

This clearly Implies : Rj = 1/30 , Rf= 1/30. In this case when they work together total time to finish this will be t=15.

But in the question they finish the work in 12 hrs. How come. The 1st statement is contradicting the question itself.

Are there any Gaps or am I misinterpreting.
Manager
Status: Employed
Joined: 17 Nov 2011
Posts: 78
Location: Pakistan
GMAT 1: 720 Q49 V40
GPA: 3.2
WE: Business Development (Internet and New Media)
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

Updated on: 18 Feb 2012, 02:57
GMATPASSION wrote:
kys123 wrote:
Statement 1 can't be correct because you don't know who out of the 2 is the faster drinker... John could drink faster than his friend or vice versa. Also you definition of average is wrong... Average mean A+B/2. A and B does not have to be the same. It could take John 50 mins to finish and Fawn 10 mins The average would still be 30

Faster drinker !!!! where does that come from???

St 1 Clearly states that "The average time it would take both to finish independently is 30 hours".

This clearly Implies : Rj = 1/30 , Rf= 1/30. In this case when they work together total time to finish this will be t=15.

But in the question they finish the work in 12 hrs. How come. The 1st statement is contradicting the question itself.

Are there any Gaps or am I misinterpreting.

Yes Mate. There is a big gap. How do you identify who is faster and who is slower. Given the information you cannot decide. The question is asking for an individual's time. Its the average time. Imagine the average time is $$30$$ hrs for both of them. This could happen in so many ways. The two values could be $$20$$ & $$40$$ or the two values could be $$10$$ & $$50$$. More importantly, we wouldn't know who accounted for which. The average of both these scenarios would be $$30$$, NO? An infinite number of possibilities exist with that "Average" information alone. Only Statement B tells us the "weight" of each contributor and tells us who was quicker. That alone should be enough information for you to pick B (along-with the fact that B limits to one variable alone), in most cases, unless it is another one of those GMAT trick questions However, this one clearly isn't and Statement B is hence enough. Since we know the relative weights of each contributor, B wins and is SUFFICIENT alone. I suggest you look up "Weighted Averages" on Wikipedia or some good Mathematics site. By the way Bunuel has composed an amazing Maths Book on the Gmat Club Forum and the more I read it, the more I realize how precise his understanding of the GMAT Quantitative section is. I seriously suggest you read it up. It will help clear a lot of tricky logic gaps. Hope I was able to explain it to you. And thanks Bunuel for pointing the error in my post.
_________________
"Nowadays, people know the price of everything, and the value of nothing." Oscar Wilde

Originally posted by omerrauf on 18 Feb 2012, 00:50.
Last edited by omerrauf on 18 Feb 2012, 02:57, edited 5 times in total.
Math Expert
Joined: 02 Sep 2009
Posts: 58369
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

18 Feb 2012, 00:59
1
omerrauf wrote:
GMATPASSION wrote:
kys123 wrote:
Statement 1 can't be correct because you don't know who out of the 2 is the faster drinker... John could drink faster than his friend or vice versa. Also you definition of average is wrong... Average mean A+B/2. A and B does not have to be the same. It could take John 50 mins to finish and Fawn 10 mins The average would still be 30

Faster drinker !!!! where does that come from???

St 1 Clearly states that "The average time it would take both to finish independently is 30 hours".

This clearly Implies : Rj = 1/30 , Rf= 1/30. In this case when they work together total time to finish this will be t=15.

But in the question they finish the work in 12 hrs. How come. The 1st statement is contradicting the question itself.

Are there any Gaps or am I misinterpreting.

Yes Mate. There is a big gap. Its the average time. Imagine the average time is 30 hrs for both of them. This could happen in so many ways. The two values could be $$20$$ & $$40$$ or the two values could be $$10$$ & $$50$$. The average of both these scenarios would be $$30$$, NO? An infinite number of possibilities exist with that "Average" information alone. Only Statement B tells us the "weight" of each contributor and that alone should be enough information for you to pick B, in most cases, unless it is another one of those GMAT trick questions However, this one clearly isn't and Statement B is hence enough. Since we know the relative weights of each contributor, B wins and is SUFFICIENT alone. Hope I was able to explain it to you.

Check the solution above: for (1) there exist only TWO combination of J and F, not more.
_________________
Manager
Status: Employed
Joined: 17 Nov 2011
Posts: 78
Location: Pakistan
GMAT 1: 720 Q49 V40
GPA: 3.2
WE: Business Development (Internet and New Media)
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

18 Feb 2012, 01:05
Yup. Right on Bunuel... My Bad....
_________________
"Nowadays, people know the price of everything, and the value of nothing." Oscar Wilde
Manager
Joined: 25 Nov 2011
Posts: 149
Location: India
Concentration: Technology, General Management
GPA: 3.95
WE: Information Technology (Computer Software)
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

18 Feb 2012, 04:12
Bunuel wrote:

But even though the formal answer to the question is B, this is not a realistic GMAT question, as: on the GMAT, two data sufficiency statements always provide TRUE information and these statements never contradict each other. In our question, from (2) we have that the average time is (30+20)/2=25 and (1) states that it's 30, so the statements clearly contradict each other.

In order it to be a realistic GMAT question (1) should read: The average time it would take John to finish the case drinking alone and Fawn to finish the case drinking alone is 25 hours. In this case for (1) we'll have: 1/J + 1/(50-J) = 1/12 --> J=30 (so F=20 --> J>F) or J=20 (so F=30 --> J<F). Statements don't contradict and (1) is still insufficient.

Hope it's clear.

Actually MGMAT flashcards did not provide the first statement. I made it up so that the whole question looks like a GMAT question. But I did not think of the point you mentioned. Great man
_________________
-------------------------
-Aravind Chembeti
Director
Joined: 07 Aug 2011
Posts: 502
GMAT 1: 630 Q49 V27
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

27 Dec 2014, 12:16
Bunuel wrote:
Chembeti wrote:
John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

This is actually from MGMAT flash cards. Looked interesting and hence I posted after modifying it a bit (I added a new statement).

John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

Given: 1/J + 1/F = 1/12

(1) The average time it would take both to finish independently is 30 hours --> J+F=60. Now, since we don't know which one drinks faster then even if we substitute F with 60-J (1/J + 1/(60-J) = 1/12) we must get two different answers for J and F: J<F and J>F. Not sufficient.

(2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case --> F=J-10 --> 1/J + 1/(J-10) = 1/12 --> J=4 (not a valid solution as F in this case is negative) and J=30 (F=20). Sufficient.

Now, technically the answer should be B, as Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

But even though the formal answer to the question is B, this is not a realistic GMAT question, as: on the GMAT, two data sufficiency statements always provide TRUE information and these statements never contradict each other. In our question, from (2) we have that the average time is (30+20)/2=25 and (1) states that it's 30, so the statements clearly contradict each other.

In order it to be a realistic GMAT question (1) should read: The average time it would take John to finish the case drinking alone and Fawn to finish the case drinking alone is 25 hours. In this case for (1) we'll have: 1/J + 1/(50-J) = 1/12 --> J=30 (so F=20 --> J>F) or J=20 (so F=30 --> J<F). Statements don't contradict and (1) is still insufficient.

Hope it's clear.

Hi Bunnel ,
(1) The average time it would take both to finish independently is 30 hours --> J+F=60. Now, if we substitute F with 60-J (1/J + 1/(60-J) = 1/12) we will get a quadratic in J with one +ive and one -ive Solution for J . Clearly J cannot be negative . so this statement should be sufficient . no ? Please advise , if i am missing something .

thanks
Math Expert
Joined: 02 Sep 2009
Posts: 58369
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

28 Dec 2014, 06:16
Lucky2783 wrote:
Bunuel wrote:
Chembeti wrote:
John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

This is actually from MGMAT flash cards. Looked interesting and hence I posted after modifying it a bit (I added a new statement).

John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

Given: 1/J + 1/F = 1/12

(1) The average time it would take both to finish independently is 30 hours --> J+F=60. Now, since we don't know which one drinks faster then even if we substitute F with 60-J (1/J + 1/(60-J) = 1/12) we must get two different answers for J and F: J<F and J>F. Not sufficient.

(2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case --> F=J-10 --> 1/J + 1/(J-10) = 1/12 --> J=4 (not a valid solution as F in this case is negative) and J=30 (F=20). Sufficient.

Now, technically the answer should be B, as Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

But even though the formal answer to the question is B, this is not a realistic GMAT question, as: on the GMAT, two data sufficiency statements always provide TRUE information and these statements never contradict each other. In our question, from (2) we have that the average time is (30+20)/2=25 and (1) states that it's 30, so the statements clearly contradict each other.

In order it to be a realistic GMAT question (1) should read: The average time it would take John to finish the case drinking alone and Fawn to finish the case drinking alone is 25 hours. In this case for (1) we'll have: 1/J + 1/(50-J) = 1/12 --> J=30 (so F=20 --> J>F) or J=20 (so F=30 --> J<F). Statements don't contradict and (1) is still insufficient.

Hope it's clear.

Hi Bunnel ,
(1) The average time it would take both to finish independently is 30 hours --> J+F=60. Now, if we substitute F with 60-J (1/J + 1/(60-J) = 1/12) we will get a quadratic in J with one +ive and one -ive Solution for J . Clearly J cannot be negative . so this statement should be sufficient . no ? Please advise , if i am missing something .

thanks

Did you try to actually solve? You'd get two solutions for J, both positive: ~17 and ~43.
_________________
CEO
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2974
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

10 Nov 2016, 00:45
Chembeti wrote:
John and Fawn, each drinking at a constant pace, can finish a case of soda together in 12 hours. How fast can John, drinking alone, finish the case?

1) The average time it would take both to finish independently is 30 hours.
2) It would take John 10 more hours to finish the case drinking alone than it would for Fawn to finish the case.

This is actually from MGMAT flash cards. Looked interesting and hence I posted after modifying it a bit (I added a new statement).

Please check the solution as attached
Attachments

File comment: www.GMATinsight.com

4.jpg [ 66.72 KiB | Viewed 2218 times ]

_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
Non-Human User
Joined: 09 Sep 2013
Posts: 13162
Re: John and Fawn, each drinking at a constant pace, can finish  [#permalink]

Show Tags

04 Apr 2019, 01:20
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: John and Fawn, each drinking at a constant pace, can finish   [#permalink] 04 Apr 2019, 01:20
Display posts from previous: Sort by