Find all School-related info fast with the new School-Specific MBA Forum

It is currently 28 Aug 2014, 07:35

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If n is a positive integer and k=5.1*10^n, what is the value

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Intern
Intern
avatar
Joined: 13 Jan 2012
Posts: 42
Followers: 0

Kudos [?]: 6 [1] , given: 0

If n is a positive integer and k=5.1*10^n, what is the value [#permalink] New post 21 Jan 2012, 08:01
1
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

100% (01:43) correct 0% (00:00) wrong based on 8 sessions
If n is a positive integer and k=5.1*10^n, what is the value of k?

(1) 6,000 < k < 500,000
(2) k^2 = 2.601 * 10^9

[Reveal] Spoiler:
OG12: DS/151:
If n is a positive integer and k = 5.1 x 10^n, what is the value of k?

(1) 6000 < k < 500,000
(2) k^2 = 2.601 x 10^9

My Response:

(1) Solving for k by trying out n = 0,1,2,3 etc. we arrive at k = 51000 for n=4. SUFFICIENT.
(2) K could be 5.1 x 10^4 or -5.1 x 10^4. NOT SUFFICIENT.

My Answer: A.

Official Answer (OG12): D.
OG12 Explanation: 2nd statement implies k can only be 5.1 x 10^4. Why not (-5.1 x 10^4) ?
[Reveal] Spoiler: OA
Kaplan GMAT Prep Discount CodesKnewton GMAT Discount CodesManhattan GMAT Discount Codes
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 22143
Followers: 3408

Kudos [?]: 24927 [1] , given: 2697

Re: If n is a positive integer and k = 5.1 x 10^n, what is k? [#permalink] New post 21 Jan 2012, 08:17
1
This post received
KUDOS
Expert's post
fxsunny wrote:
OG12: DS/151:
If n is a positive integer and k = 5.1 x 10^n, what is the value of k?

(1) 6000 < k < 500,000
(2) k^2 = 2.601 x 10^9

My Response:

(1) Solving for k by trying out n = 0,1,2,3 etc. we arrive at k = 51000 for n=4. SUFFICIENT.
(2) K could be 5.1 x 10^4 or -5.1 x 10^4. NOT SUFFICIENT.

My Answer: A.

Official Answer (OG12): D.
OG12 Explanation: 2nd statement implies k can only be 5.1 x 10^4. Why not (-5.1 x 10^4) ?


If n is a positive integer and k=5.1*10^n, what is the value of k?

As n is a positive integer then k could be: 51, 510, 5,100, 51,000, ... Also note that no matter the value of n, k is always a positive number.

(1) 6,000 < k < 500,000 --> only one number from above is in this range: 51,000. Sufficient.

(2) k^2 = 2.601 * 10^9 --> we can solve quadratics to get two values of k positive and negative, but since given that k is positive then only the positive value of k will be valid. Sufficient.

Answer: D.

Hope it's clear.

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

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; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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. ,11 Mixed Questions, 12 Fresh Meat

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., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

1 KUDOS received
Intern
Intern
avatar
Joined: 13 Jan 2012
Posts: 42
Followers: 0

Kudos [?]: 6 [1] , given: 0

Re: If n is a positive integer and k=5.1*10^n, what is the value [#permalink] New post 21 Jan 2012, 21:41
1
This post received
KUDOS
Thanks, it is. I need to pay more attention to the question.
Re: If n is a positive integer and k=5.1*10^n, what is the value   [#permalink] 21 Jan 2012, 21:41
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic What is the value of the positive integer n ? Bunuel 5 03 Jan 2014, 05:17
What is the value of the positive integer n? What is the va eybrj2 2 18 Feb 2012, 00:55
What is the value of positive integer n? Madelaine88 6 28 Feb 2011, 01:31
If N is a two-digit positive integer, what is the value of tradinggenius 2 17 Jan 2011, 23:02
Experts publish their posts in the topic If sqrt(n) is a positive integer, what is the value of n? gayathri 13 16 Jan 2005, 15:49
Display posts from previous: Sort by

If n is a positive integer and k=5.1*10^n, what is the value

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.