|
Author |
Message |
|
TAGS:
|
|
|
Intern
Joined: 06 Aug 2006
Posts: 21
Followers: 0
Kudos [?]:
2
[0], given: 2
|
Question Stats:
64% (01:41) correct
36% (00:24) wrong based on 5 sessions
Is rst = 1 ? (1) rs = 1 (2) st = 1
Last edited by Bunuel on 07 Dec 2012, 09:01, edited 1 time in total.
Renamed the topic and edited the question.
|
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11583
Followers: 1798
Kudos [?]:
9582
[1] , given: 826
|
Re: GMAT Paper test - Test Code 14 [#permalink]
 10 Feb 2010, 13:56
1
This post received
KUDOS
loki wrote: piyatiwari wrote: Answer: "E" : Both statements not sufficient
Now if both statements are taken together, r=1/3 s=3 and t=1/3 => rst not equal to 1.
hence both the statements are not sufficient. But from your response above combining the two statements tells us conclusively that rst not eqaul to 1. Therefore combining the two statements is sufficient to answer the question as a 'NO'. So shouldn't the answer be 'C' (1) rs = 1 (2) st = 1 Try r=s=t=1, both statements hold true and rst=1. Try r=s=t=-1, both statements hold true and rst=-1. Two different answers. Not sufficient. Answer: E.
_________________
PLEASE READ AND FOLLOW: 11 Rules for Posting!!!
RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory
COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. NEW!!!
DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set. NEW!!!
What are GMAT Club Tests?
25 extra-hard Quant Tests
Find out what's new at GMAT Club - latest features and updates
|
|
|
|
|
|
Senior Manager
Joined: 22 Dec 2009
Posts: 368
Followers: 9
Kudos [?]:
136
[1] , given: 47
|
Re: OG DS 95, explain how my logic is wrong [#permalink]
14 Feb 2010, 11:34
1
This post received
KUDOS
Currency wrote: Ok, without a doubt my number property skills are my achillies heel when is comes to GMAT quant. I was reviewing my error log today. Tell me why my logic is wrong. 95. Is rst=1 (1) rs=1 (2) st=1 I attacked it by rearranging the original equations, dividing both sides by t. so, rs=1/tthen sub in rs=1 so, 1=1/t then cross multiply t=1 Combined with what we already know (rs=1) we have 1*1=1 Therefore, sufficient. Same logic can be applied to statment 2. Therefore my answer was D. OA is actually E and I understand how they got it, but I also fail to see why my strategy was wrong. I feel like I'm probably overlooking some basic rule that governs all equations here but if someone could help me out that'd be great. Thanks The highlighted part is the mistake. The question is asking u to prove that... and you are considering the same as True. This isnt the correct approach. The Answer E is correct... Is rst = 1? S1: rs = 1, t can be 2 ... then rst is not equal to 1... t can be 1... then rst is equal to 1... Hence IN SUFF S2: st =1 , r can be 2 ... then rst is not equal to 1.. r can be 1 .. then rst is equal to 1... Hence IN SUFF... combining I and 2... we can have .. r = 2, s = 1/2, t = 2 Then rst = 2 but we can also have r = 1, s = 1, t =1 Then rst = 1.. Hence E... Hope this helps!
_________________
Cheers!
JT...........
If u like my post..... payback in Kudos!! 
|Do not post questions with OA|Please underline your SC questions while posting|Try posting the explanation along with your answer choice|
|For CR refer Powerscore CR Bible|For SC refer Manhattan SC Guide|
~~Better Burn Out... Than Fade Away~~
|
|
|
|
|
|
Senior Manager
Joined: 28 Jun 2009
Posts: 457
Location: United States (MA)
Followers: 14
Kudos [?]:
83
[0], given: 46
|
Re: GMAT Paper test - Test Code 14 [#permalink]
10 Feb 2010, 12:56
Answer: "E" : Both statements not sufficient
Reason:
(plugging in method)
Statement 1: Say r = 1/3 and s = 3
satisfies statement 1 i.e. rs = 1 but cant comment about value of rst as t is still unknown.
Statement 2: Say t = 1/3 and s = 3
satisfies statement 1 i.e. st = 1 but cant comment about value of rst as t is still unknown.
Now if both statements are taken together, r=1/3 s=3 and t=1/3 => rst not equal to 1.
hence both the statements are not sufficient.
|
|
|
|
|
|
Intern
Joined: 06 Aug 2006
Posts: 21
Followers: 0
Kudos [?]:
2
[0], given: 2
|
Re: GMAT Paper test - Test Code 14 [#permalink]
10 Feb 2010, 13:21
piyatiwari wrote: Answer: "E" : Both statements not sufficient
Now if both statements are taken together, r=1/3 s=3 and t=1/3 => rst not equal to 1.
hence both the statements are not sufficient. But from your response above combining the two statements tells us conclusively that rst not eqaul to 1. Therefore combining the two statements is sufficient to answer the question as a 'NO'. So shouldn't the answer be 'C'
|
|
|
|
|
|
Senior Manager
Joined: 28 Jun 2009
Posts: 457
Location: United States (MA)
Followers: 14
Kudos [?]:
83
[0], given: 46
|
Re: GMAT Paper test - Test Code 14 [#permalink]
10 Feb 2010, 13:51
loki wrote: piyatiwari wrote: Answer: "E" : Both statements not sufficient
Now if both statements are taken together, r=1/3 s=3 and t=1/3 => rst not equal to 1.
hence both the statements are not sufficient. But from your response above combining the two statements tells us conclusively that rst not eqaul to 1. Therefore combining the two statements is sufficient to answer the question as a 'NO'. So shouldn't the answer be 'C' Oh yes. My usual mistake  . Thanks so much Loki. This goes directly to my error log. So the answer is "C"
|
|
|
|
|
|
Intern
Joined: 06 Aug 2006
Posts: 21
Followers: 0
Kudos [?]:
2
[0], given: 2
|
Re: GMAT Paper test - Test Code 14 [#permalink]
10 Feb 2010, 14:04
Bunuel wrote: loki wrote: piyatiwari wrote: Answer: "E" : Both statements not sufficient
Now if both statements are taken together, r=1/3 s=3 and t=1/3 => rst not equal to 1.
hence both the statements are not sufficient. But from your response above combining the two statements tells us conclusively that rst not eqaul to 1. Therefore combining the two statements is sufficient to answer the question as a 'NO'. So shouldn't the answer be 'C' Try r=s=t=1, both statement hold true and rst=1. Try r=s=t=-1, both statement hold true and rst=-1. Two different answers. Not sufficient. Answer: E. OA is E. I get it now! Thank you!
|
|
|
|
|
|
Manager
Joined: 09 Dec 2009
Posts: 122
Followers: 3
Kudos [?]:
21
[0], given: 19
|
OG DS 95, explain how my logic is wrong [#permalink]
14 Feb 2010, 11:19
Ok, without a doubt my number property skills are my achillies heel when is comes to GMAT quant. I was reviewing my error log today. Tell me why my logic is wrong. 95. Is rst=1 (1) rs=1 (2) st=1 I attacked it by rearranging the original equations, dividing both sides by t. so, rs=1/t then sub in rs=1 so, 1=1/t then cross multiply t=1 Combined with what we already know (rs=1) we have 1*1=1 Therefore, sufficient. Same logic can be applied to statment 2. Therefore my answer was D. OA is actually E and I understand how they got it, but I also fail to see why my strategy was wrong. I feel like I'm probably overlooking some basic rule that governs all equations here but if someone could help me out that'd be great. Thanks
_________________
G.T.L. - GMAT, Tanning, Laundry
Round 1: 05/12/10 handling-a-grenade-thesituation-s-official-debrief-94181.html
Round 2: 07/10/10 - This time it's personal.
|
|
|
|
|
|
Director
Joined: 27 Jun 2008
Posts: 552
WE 1: Investment Banking - 6yrs
Followers: 1
Kudos [?]:
39
[0], given: 92
|
Re: OG DS 95, explain how my logic is wrong [#permalink]
14 Feb 2010, 11:36
Currency wrote: Ok, without a doubt my number property skills are my achillies heel when is comes to GMAT quant. I was reviewing my error log today. Tell me why my logic is wrong. 95. Is rst=1 (1) rs=1 (2) st=1 I attacked it by rearranging the original equations, dividing both sides by t. so, rs=1/t then sub in rs=1 so, 1=1/t then cross multiply t=1 Combined with what we already know (rs=1) we have 1*1=1 Therefore, sufficient. Same logic can be applied to statment 2. Therefore my answer was D. OA is actually E and I understand how they got it, but I also fail to see why my strategy was wrong. I feel like I'm probably overlooking some basic rule that governs all equations here but if someone could help me out that'd be great. Thanks Okay, you can really deal with this much simpler. But, let's review what you've done. I attacked it by rearranging the original equations, dividing both sides by t.
so, rs=1/t your question then changes to -- Is rs=1/t? 1. Does this give the vale of t? No. Even if you use (1), you get -- 1=1/t -> t=1. Does this answer your question. No. A/D out 2. Similarly, does the value of st=1, help us in answering the question? No. B out Hope this helps.
|
|
|
|
|
|
Manager
Joined: 09 Dec 2009
Posts: 122
Followers: 3
Kudos [?]:
21
[0], given: 19
|
Re: OG DS 95, explain how my logic is wrong [#permalink]
14 Feb 2010, 11:41
Quote: "The question is asking u to prove that... and you are considering the same as True. This isnt the correct approach." This is what I was missing. Normally I'd instinctively follow that, but I think cause it was in my error log I over-thought it and got fancy - effectively confusing myself. Ha! Thanks for the quick repsonses guys, much appreciated!
_________________
G.T.L. - GMAT, Tanning, Laundry
Round 1: 05/12/10 handling-a-grenade-thesituation-s-official-debrief-94181.html
Round 2: 07/10/10 - This time it's personal.
|
|
|
|
|
|
Manager
Joined: 26 Nov 2009
Posts: 180
Followers: 3
Kudos [?]:
49
[0], given: 5
|
Re: OG DS 95, explain how my logic is wrong [#permalink]
15 Feb 2010, 06:32
i) rs=1
r=1/3 s=3 and t=7 so ans is no
r=1/3 s=3 and t=1 so ans is yes
not suff.
ii) st=1
s=1/3 and t=3 and r=7 so ans is no
r=1/3 s=3 and t=1 so ans is yes
not sufficient
combining both 1 and 2
s=1/3 r=3 and t=3 still it satisfies both eq but rst is not 1
if s=1 r=1 and t=1 it satisifies both eq. and rst is 1
so ans is E
|
|
|
|
|
|
Manager
Joined: 05 Oct 2011
Posts: 169
GMAT 1: 720 Q V
Followers: 6
Kudos [?]:
34
[0], given: 55
|
Re: Is rst=1? Statement 1: rs=1 Statement 2: st=1 [#permalink]
29 Nov 2011, 12:31
i) rs=1
As we don't know anything about value of t so we cant answer if rst = 1. Insufficient.
ii) st=1
As we don't know anything about value of r so we cant answer if rst = 1. Insufficient.
Combining both 1 and 2
(rs)(st) = 1
(rst)s = 1
rst = 1/s
As we don't know the value of s. rst can be anything (1 or something else). we cannot answer "Is rst = 1?"
Insufficient
Ans: E
|
|
|
|
|
|
Intern
Joined: 15 Nov 2012
Posts: 3
Followers: 0
Kudos [?]:
0
[0], given: 1
|
Its clear that 1 and 2 do not lead to a solution. then, Cant this be solved by observing that we have 2 equations and 3 unknown variables. hence not sufficient and hence E?
|
|
|
|
|
|
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11583
Followers: 1798
Kudos [?]:
9582
[0], given: 826
|
|
|
|
|
|
|
Manager
Joined: 18 Oct 2011
Posts: 80
Location: United States
Concentration: Entrepreneurship, Marketing
GMAT Date: 01-30-2013
GPA: 3.3
Followers: 2
Kudos [?]:
9
[0], given: 0
|
statement 1: don't know anything about t. not sufficient
statement 2: don't know anything about r. not sufficient
put them together: rst could equal (1)(1)(1) in which case would be 1. or rst could equal (1/2)(2)(1/2) in which case rst = 1/2. Not sufficient
Answer: E
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
close
