It is currently 24 Feb 2018, 10:14

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Of the following sums, which is the greatest?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Current Student
User avatar
Joined: 06 Sep 2013
Posts: 1954
Concentration: Finance
GMAT ToolKit User
Of the following sums, which is the greatest? [#permalink]

Show Tags

New post 28 Sep 2013, 15:32
4
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

74% (00:52) correct 26% (00:54) wrong based on 145 sessions

HideShow timer Statistics

Of the following sums, which is the greatest?


(A) \(\frac{1}{\sqrt{2}}\) + \(\frac{1}{\sqrt{3}}\) + \(\frac{1}{\sqrt{4}}\) + \(\frac{1}{\sqrt{5}}\)

(B) \(\frac{1}{2^2}\) + \(\frac{1}{3^2}\) + \(\frac{1}{4^2}\) + \(\frac{1}{5^2}\)

(C) \(\frac{1}{2^2}\) + \(\frac{1}{2^3}\) + \(\frac{1}{2^2}\) + \(\frac{1}{2^5}\)

(D) 1- \(\frac{1}{2}\) + \(\frac{1}{3}\) - \(\frac{1}{4}\)

(E) \(\frac{1}{2}\) + \(\frac{1}{3}\) + \(\frac{1}{4}\) + \(\frac{1}{5}\)
[Reveal] Spoiler: OA
Expert Post
2 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43896
Re: Of the following sums, which is the greatest? [#permalink]

Show Tags

New post 29 Sep 2013, 09:09
2
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
jlgdr wrote:
Of the following sums, which is the greatest?

(A) \(\frac{1}{\sqrt{2}}\) + \(\frac{1}{\sqrt{3}}\) + \(\frac{1}{\sqrt{4}}\) + \(\frac{1}{\sqrt{5}}\)
(B) \(\frac{1}{2^2}\) + \(\frac{1}{3^2}\) + \(\frac{1}{4^2}\) + \(\frac{1}{5^2}\)
(C) \(\frac{1}{2^2}\) + \(\frac{1}{2^3}\) + \(\frac{1}{2^2}\) + \(\frac{1}{2^5}\)
(D) 1- \(\frac{1}{2}\) + \(\frac{1}{3}\) - \(\frac{1}{4}\)
(E) \(\frac{1}{2}\) + \(\frac{1}{3}\) + \(\frac{1}{4}\) + \(\frac{1}{5}\)


\(\sqrt{2}<2<2^2\), thus \(\frac{1}{\sqrt{2}}>\frac{1}{2}>\frac{1}{2^2}\).

Answer: A.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

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?
Extra-hard Quant Tests with Brilliant Analytics

Current Student
User avatar
Joined: 06 Sep 2013
Posts: 1954
Concentration: Finance
GMAT ToolKit User
Re: Of the following sums, which is the greatest? [#permalink]

Show Tags

New post 12 May 2014, 17:12
Any other approach for this problem over here? I did not quite get your explanation Bunuel, how can we quickly eliminate the other answer choices?

Thanks!
Cheers
J :)
2 KUDOS received
Manager
Manager
avatar
Joined: 28 Jun 2012
Posts: 52
Location: Singapore
GMAT 1: 720 Q50 V36
WE: Consulting (Consulting)
GMAT ToolKit User
Re: Of the following sums, which is the greatest? [#permalink]

Show Tags

New post 12 May 2014, 19:24
2
This post received
KUDOS
Lets compare A & E first,

sqrt(2)= 1.4 which is <2

As we know,
1/smaller > 1/larger

=>1/sqrt(2) > 1/2

so will be the case for 3,4,5

So clearly A is greater than E,

D<E, clearly because there are negative terms
B & C increase the denominators by increasing the powers, so again B & C are even lesser than E

Hence, A is the greatest

Hope this helps. Hit kudos it it does.
_________________

Do not hesitate to share appreciation, hit Kudos!!

SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1839
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: Of the following sums, which is the greatest? [#permalink]

Show Tags

New post 01 Aug 2014, 01:09
jlgdr wrote:
Any other approach for this problem over here? I did not quite get your explanation Bunuel, how can we quickly eliminate the other answer choices?

Thanks!
Cheers
J :)


One good thing of this question is numerator of all the expressions is 1

Now focus on denominators

More the value of denominator, less would be the sum

Least the denominator, more would be the sum value

\(\sqrt{2} = 2^{\frac{1}{2}}\)

\(2^{\frac{1}{2}} < 2^2\)

Reciprocal both sides

\(\frac{1}{2^{\frac{1}{2}}} > \frac{1}{2^2}\)

(Greater/smaller sign changes for reciprocals/negation)

Same for all other fractions

So highest addition would be of option A

Answer = A
_________________

Kindly press "+1 Kudos" to appreciate :)

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13764
Premium Member
Re: Of the following sums, which is the greatest? [#permalink]

Show Tags

New post 02 Oct 2017, 01:28
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Re: Of the following sums, which is the greatest?   [#permalink] 02 Oct 2017, 01:28
Display posts from previous: Sort by

Of the following sums, which is the greatest?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.