|
Author |
Message |
|
TAGS:
|
|
|
Intern
Joined: 01 Jun 2008
Posts: 11
Followers: 0
Kudos [?]:
0
[0], given: 0
|
if mv < pv < 0, is v > 0? (1) m < p (2) m < 0 [#permalink]
 03 Sep 2008, 11:44
Question Stats:
50% (00:00) correct
50% (00:40) wrong based on 6 sessions
DS question from Gmatprep - please provide explanation with answers:
if mv < pv < 0, is v > 0?
(1) m < p
(2) m < 0
|
|
|
|
|
|
|
|
|
Intern
Joined: 02 Sep 2008
Posts: 46
Followers: 0
Kudos [?]:
0
[0], given: 0
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 12:09
Answer is B.
In case 2,
As we know mv < pv <0
so mv < 0.
so v > 0 as m < 0 ( option 2).
It is more than enough to say that v > 0.
So B alone is sufficient.
In case 1,
m < p now if v is -vs then both m and p has to be +ve.
and if v is +ve then both m and p has to -ve.
So we can't tell whether v is +ve or -ve.
so A is not sufficient.
|
|
|
|
|
|
Senior Manager
Joined: 04 Jan 2006
Posts: 282
Followers: 1
Kudos [?]:
14
[0], given: 0
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 12:18
onesome68 wrote: DS question from Gmatprep - please provide explanation with answers:
if mv < pv < 0, is v > 0?
(1) m < p
(2) m < 0
I believe it is D. Case 1) m < p mv < pv < 0 mv - pv < pv - pv < -pv ...subtract pv v(m-p) < 0 < -pv Since m < p OR (m - p) < 0 Therefore, v must be positive. SUFF Case 2) m < 0 Since mv < 0 (given), v must be positive. SUFF
|
|
|
|
|
|
Manager
Joined: 09 Jul 2007
Posts: 246
Followers: 2
Kudos [?]:
18
[1] , given: 0
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 12:32
1
This post received
KUDOS
IMO D.
if mv < pv < 0, is v > 0?
(1) m < p
= > now if we mutiply both sides by a +ve number, then the inequality sign remains same and if we multiply both sides witha -ve number, the inequality sign changes.
as the sign remains same, after multiplying by V (mv < pv ) , so V >0
(2) m < 0
if v is -ve mv >0 and if v is +ve mv <0 ; as mv < 0 , v >0
|
|
|
|
|
|
SVP
Joined: 07 Nov 2007
Posts: 1837
Location: New York
Followers: 20
Kudos [?]:
297
[0], given: 5
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 12:32
devilmirror wrote: onesome68 wrote: DS question from Gmatprep - please provide explanation with answers:
if mv < pv < 0, is v > 0?
(1) m < p
(2) m < 0
I believe it is D. Case 1) m < p mv < pv < 0 mv - pv < pv - pv < -pv ...subtract pv v(m-p) < 0 < -pv Since m < p OR (m - p) < 0 Therefore, v must be positive. SUFF Case 2) m < 0 Since mv < 0 (given), v must be positive. SUFF Hey devilmirror, Agree with you. It should be D.. Little Tricky one. if mv < pv < 0, 1) m<p suffcient. mv-pv<0 --> v(m-p)<0 given m<p --> m-p<0 and v+ve 2 ) suffcient. D
_________________
Your attitude determines your altitude
Smiling wins more friends than frowning
|
|
|
|
|
|
Intern
Joined: 01 Jun 2008
Posts: 11
Followers: 0
Kudos [?]:
0
[0], given: 0
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 14:14
OA is D only ..
Thanks to all for the explanation..
|
|
|
|
|
|
VP
Joined: 05 Jul 2008
Posts: 1442
Followers: 28
Kudos [?]:
153
[0], given: 1
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 18:21
ssandeepan wrote: IMO D.
if mv < pv < 0, is v > 0?
(1) m < p
= > now if we mutiply both sides by a +ve number, then the inequality sign remains same and if we multiply both sides witha -ve number, the inequality sign changes.
as the sign remains same, after multiplying by V (mv < pv ) , so V >0
(2) m < 0
if v is -ve mv >0 and if v is +ve mv <0 ; as mv < 0 , v >0 Excellent point about the inequality and sign change you brought up. Even if we take part of the original inequality mv < pv we still have v(m-p) < 0 and we know that m < p. So V has to be +ve.
|
|
|
|
|
|
SVP
Joined: 21 Jul 2006
Posts: 1553
Followers: 6
Kudos [?]:
105
[0], given: 1
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
03 Sep 2008, 19:29
onesome68 wrote: DS question from Gmatprep - please provide explanation with answers:
if mv < pv < 0, is v > 0?
(1) m < p
(2) m < 0
First of all, since mv < pv, we know that pv - mv > 0, therefore v(p-m) > 0. So whatever is the sign for (p-m), it should be the same as that of v so that their product remains positive: (1) m < p, therefore p-m > 0, so if this is positive, then v is positive. Suff. (2) m is negative, since the product of mv from the question is negative, v must be positive. Answer is D.
|
|
|
|
|
|
Intern
Joined: 23 Jun 2010
Posts: 40
Followers: 0
Kudos [?]:
8
[0], given: 5
|
Re: Quant - DS from Gmatprep - inequality.. [#permalink]
26 Feb 2011, 13:34
ssandeepan wrote: IMO D.
if mv < pv < 0, is v > 0?
(1) m < p
= > now if we mutiply both sides by a +ve number, then the inequality sign remains same and if we multiply both sides witha -ve number, the inequality sign changes.
as the sign remains same, after multiplying by V (mv < pv ) , so V >0
(2) m < 0
if v is -ve mv >0 and if v is +ve mv <0 ; as mv < 0 , v >0 There are various ways to solve this questions. I took the longer route of picking values for variables which helped me avoid mistake I would usually make in 'visualizing' inequalities. Although you could reach the same conclusion by solving the inequalities by subtracting a term (and thus avoiding the flipping of inequality sign required when multiplying/dividing with a -ve variable), the solution you provides is just excellent. A simple observation of the original question and the first statement already saves a ton of calculations and mistakes. Valuable point! Kudos!
_________________
-DK
---------------------------------------------------------
If you like what you read then give a Kudos! 
Diagnostic Test: 620
The past is a guidepost, not a hitching post.
---------------------------------------------------------
|
|
|
|
|
|
|
Re: Quant - DS from Gmatprep - inequality..
[#permalink]
26 Feb 2011, 13:34
|
|
|
|
|
|
|
|
|
|
|
close
