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

 It is currently 18 Jul 2018, 22:37

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

A swimmer makes a round trip up and down the river. It takes

Author Message
Intern
Joined: 26 Aug 2005
Posts: 48
A swimmer makes a round trip up and down the river. It takes [#permalink]

Show Tags

17 May 2008, 18:41
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions

HideShow timer Statistics

A swimmer makes a round trip up and down the river. It takes him x hours. The next day he swims the same distance with the same speed in the still water. It takes him y hours. What can we say about x and y ?

a) x>y
b) x<y
c) x=y
d) x=y/2
e) none of the above

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Director
Joined: 23 Sep 2007
Posts: 761

Show Tags

17 May 2008, 19:20
E

we don't know if the swimmer swamp up river during high tide, and down the river during high tide

or up river during high tide and down river during low tide

or up river during low tide and down river during low tide

or up river during low tide and down river during high tide
CEO
Joined: 17 Nov 2007
Posts: 3484
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40

Show Tags

17 May 2008, 19:30
1
A

1. fast way: Let imagine that the speed of the river is very close to the speed of the swimmer. So, when the swimmer is swiming up it can take a very long time and it is obvious that x>>y. So, A

2. usual way:

let V - the speed of the swimmer
U - the speed of the river
L - length of the round trip

$$y=\frac{L}{V}$$

$$x=\frac{\frac12*L}{V-U}+\frac{\frac12*L}{V+U}=L*\frac{V}{V^2-U^2}>L*\frac{V}{V^2-0^2}=L*\frac{1}{V}=y$$

So, x>y
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

VP
Joined: 28 Dec 2005
Posts: 1482

Show Tags

17 May 2008, 19:51
how can we tell anything about x and y's relation from the info given ? we dont know if the initial round trip was done in still water or not , etc.

thats why i went for E
CEO
Joined: 17 Nov 2007
Posts: 3484
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40

Show Tags

17 May 2008, 20:00
pmenon wrote:
how can we tell anything about x and y's relation from the info given ? we dont know if the initial round trip was done in still water or not , etc.

I think that river has always flow and additionally "up" as well as "down" in the phrase "A swimmer makes a round trip up and down the river." say that river has flow.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

VP
Joined: 28 Dec 2005
Posts: 1482

Show Tags

17 May 2008, 20:02
i agree that if the question made any clear mention of the initial trip having the swimmer go against/with some current, the answer might be different ... but i dont know if we can make that assumption here.

Im stumped ... although I wont be too concerned if i was wrong because i dont think this is a real GMAT type question ... i hope
CEO
Joined: 17 Nov 2007
Posts: 3484
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40

Show Tags

17 May 2008, 20:14
Yes, all GMAT questions are airtight! I have not seen any vague questions from real GMAT sources.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Manager
Joined: 14 May 2008
Posts: 57
Schools: Wharton (WEMBA East)

Show Tags

18 May 2008, 07:31
Even if he swims the first day with current, he swims up and down, halfway with current against him, halfway with current behind him. Who's to say whether this is faster/slower/same as swimming with zero current?

Sure, we don't know about his conditioning relative to the level of effort required for this swim, but you could argue that the effort expended swimming against the current might not be fully offset by the effort saved swimming with it.

Either way, I'd go e.) because there's not enough detail about the first day's swim to model it discretely.
Manager
Joined: 16 Oct 2008
Posts: 54

Show Tags

12 Nov 2008, 02:56
seongbae wrote:
A swimmer makes a round trip up and down the river. It takes him x hours. The next day he swims the same distance with the same speed in the still water. It takes him y hours. What can we say about x and y ?

a) x>y
b) x<y
c) x=y
d) x=y/2
e) none of the above

I found this Q from old post.

I got A, don't know if I'm correct

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: PS: Swimmer   [#permalink] 12 Nov 2008, 02:56
Display posts from previous: Sort by

A swimmer makes a round trip up and down the river. It takes

Moderators: chetan2u, KarishmaB, Bunuel, niks18

Events & Promotions

 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®.