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 →

5 power k

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 1179
Joined: Sun Apr 11, 2010 9:07 pmFollowed by: 88 members
Location: Milpitas, CA
Thanked: 447 times

by Rahul@gurome » Sat Sep 11, 2010 8:53 am
sairamGmat wrote:. Is 5^k less than 1,000 ?
(1) 5^ (k-1) >3000
(2) 5^(k-1) = 5^k - 500

Official Answer is B

Can any one explain why is this so?
Please see the attachment.
Attachments
Exponents.doc
(24.5 KiB) Downloaded 152 times
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 160
Joined: Mon Apr 05, 2010 4:41 am
Thanked: 7 times

by gmat1011 » Sat Sep 11, 2010 10:06 am
In stem 1 if 5 to the power k >15000 then doesnt it imply that 5^k is certainly NOT less than 1,000 (its a number in excess of 15,000) --- so it is sufficient to answer the question and so D?

But if thats the case stem 1 and stem 2 would be providing different answers with respect to the possible value of 5^k (GMAT questions do not have contradictory stems)...

But 1 does look sufficient on its terms to me. Rahul@gurome can you please explain? Thanks for your time.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 1179
Joined: Sun Apr 11, 2010 9:07 pmFollowed by: 88 members
Location: Milpitas, CA
Thanked: 447 times

by Rahul@gurome » Sat Sep 11, 2010 8:48 pm
gmat1011 wrote:In stem 1 if 5 to the power k >15000 then doesnt it imply that 5^k is certainly NOT less than 1,000 (its a number in excess of 15,000) --- so it is sufficient to answer the question and so D?

But if thats the case stem 1 and stem 2 would be providing different answers with respect to the possible value of 5^k (GMAT questions do not have contradictory stems)...

But 1 does look sufficient on its terms to me. Rahul@gurome can you please explain? Thanks for your time.
5^k > 15,000 or 15,000 < 5^k only gives us the that 5^k cannot exceed 15,000 but can we not say that 5^k < ___. So it only gives us the upper range not the lower one. 15,000 < 5^k < ___________ How can we fill in this blank?

Does this help?
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 160
Joined: Mon Apr 05, 2010 4:41 am
Thanked: 7 times

by gmat1011 » Sat Sep 11, 2010 11:39 pm
5^k > 15,000 or 15,000 < 5^k I thought means 5^k is a value greater than 15000 --- 15k is like a 'floor' value the value of 5^k cannot hit (I learned it at school with the teacher pointing out that the greater value points the 'beak' at the lower value!)

5^k < 15,000 or 15,000 > 5^k on the other hand would mean 5^k is less than 15000, i.e., 15000 is a 'ceiling' on the value

15,000 < 5^k < ___________ --- would mean 5^k lies in a certain positive value range


Even though the precise value of 5^k is not known - what is known for sure is that it is a value in excess of 15,000 => it can certainly not be less than 1000, what ever it is... and that makes it sufficient to answer the question asked: Is 5^k less than 1,000 ?

Do you always need a precise value on GMAT DS to conclude sufficiency --- this would be a good practical point to note if thats the case... but on its terms stem 1 seems to provide what one needs?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 10
Joined: Sun Jun 20, 2010 8:33 am
Thanked: 1 times
GMAT Score:730

by watchout4me » Sun Sep 12, 2010 3:11 am
To me, statement 1 is sufficient.

Rahul_gurome,
If 5 ^ k > 15,000, then can't we conclusively say 5 ^ k is not less than 1000? The question just says 'Is 5 ^ k < 1000?' . We can answer 'No' using statement 1 and hence statement 1 is sufficient.
I do not understand your explanation. Can you elaborate and let me know where I am making a mistake, if any?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pmFollowed by: 7 members
Thanked: 215 times

by kvcpk » Sun Sep 12, 2010 3:57 am
Rahul@gurome wrote: 5^k > 15,000 or 15,000 < 5^k only gives us the that 5^k cannot exceed 15,000 but can we not say that 5^k < ___. So it only gives us the upper range not the lower one. 15,000 < 5^k < ___________ How can we fill in this blank?

Does this help?
Hi Rahul,

You are missing something.
5^k>15000 means that 5^k>1000
We dont need to check again what 5^k is less than.
it might be like this: 15000<5^k<25000
But we are really not concerned with the upper limit.
Lower limit is 15000 which is greater than 1000.

You just got confused for once I believe.I know your credibility on this forum though.
"Once you start working on something,
don't be afraid of failure and don't abandon it.
People who work sincerely are the happiest."
Chanakya quotes (Indian politician, strategist and writer, 350 BC-275BC)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1893
Joined: Sun May 30, 2010 11:48 pmFollowed by: 7 members
Thanked: 215 times

by kvcpk » Sun Sep 12, 2010 3:59 am
I think stmt1 should be 5^(k+1)>3000 instead of 5^(k-1)>3000
"Once you start working on something,
don't be afraid of failure and don't abandon it.
People who work sincerely are the happiest."
Chanakya quotes (Indian politician, strategist and writer, 350 BC-275BC)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 1179
Joined: Sun Apr 11, 2010 9:07 pmFollowed by: 88 members
Location: Milpitas, CA
Thanked: 447 times

by Rahul@gurome » Sun Sep 12, 2010 4:02 am
kvcpk wrote:
Hi Rahul,
You are missing something.
5^k>15000 means that 5^k>1000
We dont need to check again what 5^k is less than.
it might be like this: 15000<5^k<25000
But we are really not concerned with the upper limit.
Lower limit is 15000 which is greater than 1000.

You just got confused for once I believe.I know your credibility on this forum though.
You are right, (1) is SUFFICIENT here. Thanks for pointing that out!
The correct answer is (D) here.
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1