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If mv<pv<0, is v>0?

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caralodigiani
 Post subject: If mv<pv<0, is v>0?
 Post Posted: Sun Sep 19, 2010 7:33 pm 
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Posts: 4
GMAT Prep - CAT #2 - Data Sufficiency

If mv<pv<0, is v>0?
(1) m<p
(2) m<0

Can you help me figure this out. Thank you!
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parthatayi
 Post subject: Re: If mv<pv<0, is v>0?
 Post Posted: Mon Sep 20, 2010 12:41 am 
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Course Students


Posts: 40
caralodigiani wrote:
GMAT Prep - CAT #2 - Data Sufficiency

If mv<pv<0, is v>0?
(1) m<p
(2) m<0

Can you help me figure this out. Thank you!


Consider statement (1)

Consider m=-1
and p=-2
=> v>0 for mv<pv<0 to be true

Consider m=1 and p=2
=> v<0 for mv<pv<0 to be true

Hence it cannot be answered with statement 1 alone.

Consider statement 2:
m<0
As mv<0
=> v>0

As it can be answered with statement 2 alone
the OA must be B

Thanks and Regards,
Partha.
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gokul_nair1984
 Post subject: Re: If mv<pv<0, is v>0?
 Post Posted: Mon Sep 20, 2010 4:48 am 
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Students


Posts: 170
parthatayi wrote:
Consider statement (1)

Consider m=-1
and p=-2
=> v>0 for mv<pv<0 to be true


You have misinterpreted the statement:
If mv<pv<0, is v>0?
(1) m<p
(2) m<0
-1>-2, whereas m<p.
So let's take m=-1 and p=0
Substituting in the stem ,we get,
-v<0 or v>0. Hence A is also sufficient.
So the answer has to be D
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parthatayi
 Post subject: Re: If mv<pv<0, is v>0?
 Post Posted: Tue Sep 21, 2010 8:51 pm 
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Course Students


Posts: 40
gokul_nair1984 wrote:
parthatayi wrote:
Consider statement (1)

Consider m=-1
and p=-2
=> v>0 for mv<pv<0 to be true


You have misinterpreted the statement:
If mv<pv<0, is v>0?
(1) m<p
(2) m<0
-1>-2, whereas m<p.
So let's take m=-1 and p=0
Substituting in the stem ,we get,
-v<0 or v>0. Hence A is also sufficient.
So the answer has to be D



yes I stand corrected.
For statement 1, please consider
m=-2 and p=-1,
m=1 and p=2.

You cannot cannot take p=0 as this fails the main condition
mv<pv<0.If p=0 then pv=0 which is false.

Thanks and Regards,
Partha.
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RonPurewal
 Post subject: Re: If mv<pv<0, is v>0?
 Post Posted: Mon Oct 04, 2010 8:26 am 
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ManhattanGMAT Staff


Posts: 7146
caralodigiani wrote:
GMAT Prep - CAT #2 - Data Sufficiency

If mv<pv<0, is v>0?
(1) m<p
(2) m<0

Can you help me figure this out. Thank you!


first, make sure you understand how to handle this particular kind of pesky data sufficiency question -- the type in which "if", followed by a statement, occurs in the question prompt.

if you have "IF" followed by stuff in a DS PROMPT, then get that fact out of the prompt, and into the answer choices. i.e., IMMEDIATELY, before you even turn on your brain.

i.e.

if you see

"If THIS, then QUESTION ?
(1) THAT
(2) THE OTHER THING"

you should IMMEDIATELY rephrase this to:

QUESTION ?
(1) THIS and THAT
(2) THIS and THE OTHER THING


so here you get:

is v>0?
(1) mv<pv<0 and m<p
(2) mv<pv<0 and m<0

now let's decode "mv < pv < 0".
there are only two ways in which this can occur:
(1) v < 0
in this case, divide the left-hand inequality by v, to produce m > p.
(2) v > 0
in this case, divide the left-hand inequality by v, to produce m < p.

so,
"mv < pv < 0" means
EITHER v < 0 and m > p (*),
OR v > 0 and m < p. (**)

--

statement (1)
this must be case (**)
so, yes, v > 0
sufficient

statement (2)
we have m < 0 and mv < 0 (ignore pv this time), so v must be positive.
so, this is (**) again
sufficient

(D)
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nileshpatil42
 Post subject: Re: If mv<pv<0, is v>0?
 Post Posted: Thu Oct 07, 2010 6:15 am 
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Students


Posts: 1
But in GMATPREP the answer is only Statement 1 is sufficient and not 2
I cant post that screenshot here:(
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tim
 Post subject: Re: If mv<pv<0, is v>0?
 Post Posted: Fri Oct 08, 2010 4:02 am 
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ManhattanGMAT Staff


Posts: 2242
Location: Southwest Airlines, seat 21C
And yet you didn’t post the screenshot. :) Ron’s absolutely right. I suspect if you post a screenshot that lists the answer as A then we’ll find that the problem has been transcribed incorrectly..

_________________
Tim Sanders
Manhattan GMAT Instructor
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