BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Fun with r!

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Fri Feb 27, 2009 8:38 pm
by TryHarder » Fri May 29, 2009 6:24 pm
Is rs = rx - 2?
1. r is an odd number
2. x = s + 2

Note: For those of you who have seen this question in the official source, try not to copy the official explanation. Is is not very convincing, hence this query.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
Master | Next Rank: 500 Posts
Posts: 103
Joined: Mon May 18, 2009 9:47 am
Thanked: 19 times

by raleigh » Fri May 29, 2009 8:00 pm
(1) r is odd.
Choose r = 1, s = 2, x = 4. Then rs = 2, rx - 2 = 2.
Choose r = 1, s = 2, x = 2. Then rs = 2, rx - 2 = 0.

Insufficient.

(2) x = s + 2. Substitute this into rx - 2 = r (s + 2) - 2 = rs + 2r - 2.

Set this equal to rs and we see this will be valid for rs= rs + 2r - 2 which simplifies to r=1.

Choose r = 1, x = 1, s = -1. Then rs = -1, and rx - 2 = 1 -2 = -1.
Choose r = 3, x = 2, s = 0. Then rs = 0, and rx - 2 = 6 - 2 = 4.

Insufficient.

(1)+(2)
Notice that in (2) we chose r to be odd in both cases. So the argument for (2) applies to this case.

Insufficient.

The answer is E.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Fri Feb 27, 2009 8:38 pm

by TryHarder » Fri May 29, 2009 8:29 pm
raleigh,
I came up with the same answer, but the official answer is B, even though is is true only when r=2.

Came an expert shed some light on this?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 103
Joined: Mon May 18, 2009 9:47 am
Thanked: 19 times

by raleigh » Fri May 29, 2009 8:54 pm
My counter example for (2) is correct so it cannot be B.

The OA is incorrect unless you mistyped the problem. Which problem is this in the OG?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Fri Feb 27, 2009 8:38 pm

by TryHarder » Fri May 29, 2009 8:59 pm
I think you misunderstood my point, I did imply that I too think the answer should be E for the very obvious reason that statement 2 is true only for r=2 and not always. Also, there is nothing wrong with the problem as stated.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 103
Joined: Mon May 18, 2009 9:47 am
Thanked: 19 times

by raleigh » Fri May 29, 2009 9:05 pm
I understand your point. I'd like to see the actual OA; what book is this from and what is the number for this problem? It has to be wrong.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Fri Feb 27, 2009 8:38 pm

by TryHarder » Fri May 29, 2009 9:32 pm
McGraw Hills GMAT 2009 Practice Test 3: Q27
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Sat May 30, 2009 2:28 am

by greymatter » Sat May 30, 2009 2:57 am
yes E.
B would have been the answer if it also tells us that r =1; which is is not so.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Mon Jun 01, 2009 1:55 am

by riya.sharma.sweet1984 » Mon Jun 01, 2009 1:58 am
Answer E :D
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 1169
Joined: Sun Jul 06, 2008 2:34 amFollowed by: 1 member
Thanked: 25 times

by aj5105 » Mon Jun 01, 2009 3:58 am
In statement (2), we get r = 1. In the part underlined, you chose r = 3

Is this right? Please clarify.

IMO, you can as well use the same values what you used in Statement (1)

raleigh wrote:(1) r is odd.
Choose r = 1, s = 2, x = 4. Then rs = 2, rx - 2 = 2.
Choose r = 1, s = 2, x = 2. Then rs = 2, rx - 2 = 0.

Insufficient.

(2) x = s + 2. Substitute this into rx - 2 = r (s + 2) - 2 = rs + 2r - 2.

Set this equal to rs and we see this will be valid for rs= rs + 2r - 2 which simplifies to r=1.

Choose r = 1, x = 1, s = -1. Then rs = -1, and rx - 2 = 1 -2 = -1.
Choose r = 3, x = 2, s = 0. Then rs = 0, and rx - 2 = 6 - 2 = 4.

Insufficient.

(1)+(2)
Notice that in (2) we chose r to be odd in both cases. So the argument for (2) applies to this case.

Insufficient.

The answer is E.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 139
Joined: Wed Oct 22, 2008 4:36 am
Thanked: 17 times

by sacx » Mon Jun 01, 2009 5:21 am
r0 + s = r0 + x - 2
s = x -2
x = s +2

STMT I

Does not tell anything about s or x

Insuff

STMT II

this is what the question is asking

Insuff

STMT I & II

Insuff, as we do not know anything about s or x

E
SACX
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1