Manatees, aquatic mammals inhabiting Florida s rivers and : GMAT Critical Reasoning (CR)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 22 Jan 2017, 19:49

### 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

# Manatees, aquatic mammals inhabiting Florida s rivers and

Author Message
TAGS:

### Hide Tags

Director
Joined: 24 Aug 2007
Posts: 954
WE 1: 3.5 yrs IT
WE 2: 2.5 yrs Retail chain
Followers: 76

Kudos [?]: 1272 [3] , given: 40

Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

19 Jun 2010, 08:25
3
KUDOS
11
This post was
BOOKMARKED
00:00

Difficulty:

75% (hard)

Question Stats:

58% (02:14) correct 42% (01:38) wrong based on 728 sessions

### HideShow timer Statistics

Manatees, aquatic mammals inhabiting Florida’s rivers and coastal waters, swim close to the surface and are frequently killed in collisions with boats. To address the problem, boat traffic in manatee-populated waters is being required to maintain very low speeds. Unfortunately, manatees are unable to hear low-pitched sounds and a boat’s sound lowers in pitch as the boat slows. Therefore, this approach may in fact make things worse rather than better.

Which of the following, if true, casts most doubt on the conclusion?

A. The areas where boats would have to maintain low speeds were decided partly on the basis of manatee-population estimates and partly from numbers of reported collisions between manatees and boats.
B. Because the water hyacinth that manatees feed on grows best in water that is nearly still, water hyacinth beds can be disturbed or damaged by fast-moving boat traffic.
C. Over the last several decades, boat traffic in Florida’s coastal waters has been increasing almost continuously and now represents the greatest threat to the endangered manatee population.
D. The sound of a boat engine generally travels much further under water than it does through the air.
E. When experimenters exposed manatees to the recorded sounds of boats moving at various speeds, the creatures were unable to discern the sounds over normalbackground noise.

I marked the OA by PoE, but I was not much clear on the argument. Can someone explain on the argument and answer choice?
[Reveal] Spoiler: OA

_________________

Tricky Quant problems: http://gmatclub.com/forum/50-tricky-questions-92834.html
Important Grammer Fundamentals: http://gmatclub.com/forum/key-fundamentals-of-grammer-our-crucial-learnings-on-sc-93659.html

Last edited by RaviChandra on 12 Aug 2015, 20:30, edited 2 times in total.
If you have any questions
New!
Senior Manager
Joined: 25 Feb 2010
Posts: 481
Followers: 4

Kudos [?]: 84 [0], given: 10

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 06:43
IMO B
_________________

GGG (Gym / GMAT / Girl) -- Be Serious

Its your duty to post OA afterwards; some one must be waiting for that...

Intern
Joined: 12 May 2010
Posts: 22
Followers: 0

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

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 06:53
D
Intern
Joined: 25 May 2010
Posts: 20
Followers: 0

Kudos [?]: 12 [11] , given: 1

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 10:10
11
KUDOS
I think the answer is E.

The hypothesis is that boats traveling slow = less manatees killed. However, manatees can't hear slow boats and therefore, slow boats will make the problem WORSE. The argument is saying that boats traveling at various speeds will kill less manatees than all boats traveling slowly on the account that manatees can't hear slow boats.

To cast doubt on this, we can show that manatees can't hear various speeds. Thus, mandating slow boats will not make the problem WORSE, it should stay the same.
Manager
Joined: 17 Oct 2008
Posts: 196
Followers: 1

Kudos [?]: 25 [0], given: 11

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 10:26
IMO B.
water hyacinth beds can be disturbed or damaged by fast-moving boat
traffic. when Boats maintain low speeds, it cant worsen things.

OA?
Director
Status: Impossible is not a fact. It's an opinion. It's a dare. Impossible is nothing.
Affiliations: University of Chicago Booth School of Business
Joined: 26 Nov 2009
Posts: 997
Location: Singapore
Followers: 22

Kudos [?]: 747 [0], given: 36

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 21:00
Yes B.

Apply negation on B. And arg will reverse.
_________________

Please press kudos if you like my post.

Intern
Joined: 14 May 2010
Posts: 33
Schools: CBS
Followers: 0

Kudos [?]: 8 [0], given: 1

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 22:36
E...if they cannot distinguish different boat sounds, there won't be much difference (the situation will maybe improve), and the conclusion is weakened...
Director
Status: Impossible is not a fact. It's an opinion. It's a dare. Impossible is nothing.
Affiliations: University of Chicago Booth School of Business
Joined: 26 Nov 2009
Posts: 997
Location: Singapore
Followers: 22

Kudos [?]: 747 [1] , given: 36

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

20 Jun 2010, 23:43
1
KUDOS
Now I am hesitant on B. But the only contenders are B / E.

E is only one which DELINKS the speed of boat as the key force of the argument.
_________________

Please press kudos if you like my post.

Manager
Joined: 16 Jun 2010
Posts: 171
Followers: 3

Kudos [?]: 40 [0], given: 1

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

21 Jun 2010, 00:50
E IMO We are supposed to logically negate the argument. E does that by making the stituation from worse ------ > Same .

QA plz ?
_________________

R E S P E C T

Finally KISSedGMAT 700 times 450 to 700 An exprience

Manager
Joined: 24 Dec 2009
Posts: 224
Followers: 2

Kudos [?]: 39 [0], given: 3

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

21 Jun 2010, 08:11
I believe the answer should be E. B though mentions that fast boats can kill the manatees, but no where it mentions if the slow boats are going to help and reduce the collisions.

B answer choice is like a Shell game.

Thanks,
Akhil M.Parekh
Director
Status: Impossible is not a fact. It's an opinion. It's a dare. Impossible is nothing.
Affiliations: University of Chicago Booth School of Business
Joined: 26 Nov 2009
Posts: 997
Location: Singapore
Followers: 22

Kudos [?]: 747 [0], given: 36

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

21 Jun 2010, 09:13
What is a shell game? How is it affecting the argument?

amp0201 wrote:
I believe the answer should be E. B though mentions that fast boats can kill the manatees, but no where it mentions if the slow boats are going to help and reduce the collisions.

B answer choice is like a Shell game.

Thanks,
Akhil M.Parekh

_________________

Please press kudos if you like my post.

Manager
Joined: 24 Dec 2009
Posts: 224
Followers: 2

Kudos [?]: 39 [0], given: 3

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

21 Jun 2010, 13:02
Shell game is like the answer choice most similar to correct one, though not the correct one.

The argument's conclusion is - slower boats might worsen the problem.

Answer choice E says Manatees are not able to hear noises at any levels. Hence the problem won't worsen but will stay same.

Hence I believe to be E rather than B. Thank You.

Thanks,
Akhil M.Parekh
Intern
Joined: 20 May 2010
Posts: 25
Followers: 1

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

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

22 Jun 2010, 02:17
E
Intern
Joined: 17 Nov 2009
Posts: 46
Followers: 1

Kudos [?]: 7 [0], given: 2

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

22 Jun 2010, 10:47
E ?
Director
Joined: 24 Aug 2007
Posts: 954
WE 1: 3.5 yrs IT
WE 2: 2.5 yrs Retail chain
Followers: 76

Kudos [?]: 1272 [0], given: 40

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

22 Jun 2010, 11:29
OA is E. Good catch by krypt.
_________________

Tricky Quant problems: http://gmatclub.com/forum/50-tricky-questions-92834.html
Important Grammer Fundamentals: http://gmatclub.com/forum/key-fundamentals-of-grammer-our-crucial-learnings-on-sc-93659.html

Senior Manager
Joined: 25 Feb 2010
Posts: 481
Followers: 4

Kudos [?]: 84 [0], given: 10

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

22 Jun 2010, 20:17
krypt wrote:
I think the answer is E.

The hypothesis is that boats traveling slow = less manatees killed. However, manatees can't hear slow boats and therefore, slow boats will make the problem WORSE. The argument is saying that boats traveling at various speeds will kill less manatees than all boats traveling slowly on the account that manatees can't hear slow boats.

To cast doubt on this, we can show that manatees can't hear various speeds. Thus, mandating slow boats will not make the problem WORSE, it should stay the same.

what's the background sound means here; They'll not be able to distinguish b/w Boat noise and normal noise?
_________________

GGG (Gym / GMAT / Girl) -- Be Serious

Its your duty to post OA afterwards; some one must be waiting for that...

Forum Moderator
Status: mission completed!
Joined: 02 Jul 2009
Posts: 1426
GPA: 3.77
Followers: 180

Kudos [?]: 853 [3] , given: 621

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

26 Jul 2010, 01:37
3
KUDOS
2
This post was
BOOKMARKED
E.
Seemed easy to me.

because boats drive fast they kill manatee.
Why? there are two reasons: either manatees are sluggish or deaf.
conclusion: author says that deafness kills M. we must introduce evidence that would make author to reconsider his her conclusion by saying "ohh... I am stupid I did not account for this"

E says that M can't discern sounds, so they die not due to deafness, but becuase they are sluggish.
_________________

Audaces fortuna juvat!

GMAT Club Premium Membership - big benefits and savings

Manager
Joined: 10 Feb 2008
Posts: 90
Followers: 1

Kudos [?]: 29 [0], given: 2

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

26 Jul 2010, 03:26
on reverification got E as correct
wasted approx 6 min
_________________

-------------------------------------------------------------------------------------------
Amar
http://amarnaik.wordpress.com

Manager
Joined: 09 Jul 2010
Posts: 150
Followers: 1

Kudos [?]: 26 [0], given: 3

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

26 Jul 2010, 20:54
i also thought B
but E it shud be
_________________

consider cudos if you like my post

SVP
Joined: 16 Jul 2009
Posts: 1628
Schools: CBS
WE 1: 4 years (Consulting)
Followers: 42

Kudos [?]: 1059 [0], given: 2

Re: Manatees, aquatic mammals inhabiting Florida s rivers and [#permalink]

### Show Tags

07 Jan 2011, 05:42
B if something, strengthenes the argument saying that slow boats is a good plan.
_________________

The sky is the limit
800 is the limit

GMAT Club Premium Membership - big benefits and savings

Re: Manatees, aquatic mammals inhabiting Florida s rivers and   [#permalink] 07 Jan 2011, 05:42

Go to page    1   2    Next  [ 31 posts ]

Similar topics Replies Last post
Similar
Topics:
3 Manatees, aquatic mammals inhabiting Florida s rivers and 2 21 Nov 2010, 03:12
1 Manatees, aquatic mammals inhabiting Florida s rivers and 7 19 Feb 2009, 09:45
Manatees, aquatic mammals inhabiting Florida s rivers and 10 27 Apr 2008, 11:05
Manatees, aquatic mammals inhabiting Florida s rivers and 7 06 Oct 2007, 18:46
Manatees, aquatic mammals inhabiting Florida s rivers and 6 01 Jun 2007, 08:48
Display posts from previous: Sort by