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

It is currently 25 Jul 2016, 03:47
GMAT Club Tests

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

Root(80)+root(125)

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

Hide Tags

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 34038
Followers: 6080

Kudos [?]: 76383 [1] , given: 9973

Root(80)+root(125) [#permalink]

Show Tags

New post 01 Oct 2012, 05:02
1
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

91% (01:40) correct 9% (01:22) wrong based on 771 sessions

HideShow timer Statistics

2 KUDOS received
Moderator
Moderator
User avatar
Joined: 01 Sep 2010
Posts: 2992
Followers: 691

Kudos [?]: 5553 [2] , given: 968

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 01 Oct 2012, 07:43
2
This post received
KUDOS
Whe we deal with this problems may be the best thing to do is to break the number into factors

\(\sqrt{80}\)\(=\)\(\sqrt{2*5*2*2*2}\) ---> \(\sqrt{4*4*5}\) ---> \(4\)\(\sqrt{5}\)

\(\sqrt{125}\) \(=\) \(\sqrt{25 *5}\) -----> \(5\) \(\sqrt{5}\)

\(4\)\(\sqrt{5}\) \(+ 5\) \(\sqrt{5}\) \(=\) \(9\)\(\sqrt{5}\)

A should be the answer
_________________

COLLECTION OF QUESTIONS AND RESOURCES
Quant: 1. ALL GMATPrep questions Quant/Verbal 2. Bunuel Signature Collection - The Next Generation 3. Bunuel Signature Collection ALL-IN-ONE WITH SOLUTIONS 4. Veritas Prep Blog PDF Version 5. MGMAT Study Hall Thursdays with Ron Quant Videos
Verbal:1. Verbal question bank and directories by Carcass 2. MGMAT Study Hall Thursdays with Ron Verbal Videos 3. Critical Reasoning_Oldy but goldy question banks 4. Sentence Correction_Oldy but goldy question banks 5. Reading-comprehension_Oldy but goldy question banks

1 KUDOS received
Intern
Intern
avatar
Joined: 30 Aug 2011
Posts: 22
Location: United States
Concentration: General Management, International Business
Schools: ISB '15
GMAT 1: 680 Q46 V37
WE: Project Management (Computer Software)
Followers: 0

Kudos [?]: 15 [1] , given: 17

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 04 Oct 2012, 00:50
1
This post received
KUDOS
\(\sqrt{80} = \sqrt{16*5} = 4\sqrt{5}\) ........(1)

\(\sqrt{125} = \sqrt{25*5} = 5\sqrt{5}\) .......(2)

Thus \(4\sqrt{5} + 5\sqrt{5} = 9\sqrt{5}\)

Thus answer is A
1 KUDOS received
Intern
Intern
avatar
Joined: 01 Jan 2015
Posts: 33
Location: India
GPA: 3.71
WE: Consulting (Retail Banking)
Followers: 3

Kudos [?]: 45 [1] , given: 14

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 04 May 2016, 10:06
1
This post received
KUDOS
A
80=4*4*5
125=5*5*5
Root(80)=4Root(5)
Similarly 125
hence 9Root(5)
_________________

_________________
"Kudos please :)"

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 34038
Followers: 6080

Kudos [?]: 76383 [0], given: 9973

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 01 Oct 2012, 05:03
Expert's post
Director
Director
avatar
Joined: 24 Aug 2009
Posts: 504
Schools: Harvard, Columbia, Stern, Booth, LSB,
Followers: 12

Kudos [?]: 604 [0], given: 241

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 01 Oct 2012, 19:42
Answer is A (Same explanation as Carcass's)
_________________

If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS.
Kudos always maximizes GMATCLUB worth
-Game Theory

If you have any question regarding my post, kindly pm me or else I won't be able to reply

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 34038
Followers: 6080

Kudos [?]: 76383 [0], given: 9973

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 04 Oct 2012, 13:59
Expert's post
SOLUTION

\(\sqrt{80}+\sqrt{125} =\)

(A) \(9\sqrt{5}\)
(B) \(20\sqrt{5}\)
(C) \(41\sqrt{5}\)
(D) \(\sqrt{205}\)
(E) 100

\(\sqrt{80}+\sqrt{125} =\sqrt{16*5}+\sqrt{25*5}=4\sqrt{5}+5\sqrt{5}=9\sqrt{5}\).

Answer: A.

Kudos points given to everyone with correct solution. Let me know if I missed someone.
_________________

New to the Math Forum?
Please read this: 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

Manager
Manager
avatar
Joined: 25 Jun 2012
Posts: 71
Location: India
WE: General Management (Energy and Utilities)
Followers: 4

Kudos [?]: 87 [0], given: 15

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 05 Oct 2012, 04:46
.
sqt80=4sqrt5
sqrt125=5sqrt5

total = 9sqrt5
Director
Director
User avatar
Status: Final Countdown
Joined: 17 Mar 2010
Posts: 563
Location: India
GPA: 3.82
WE: Account Management (Retail Banking)
Followers: 16

Kudos [?]: 244 [0], given: 75

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 06 Oct 2012, 10:24
\sqrt{80} + \sqrt{125}

\sqrt{2x2x2x2x5} + \sqrt{5x5x5}

4\sqrt{5} + 5\sqrt{5}

\sqrt{5} ( 4+5)

9\sqrt{5}

Ans: A
_________________

" Make more efforts "
Press Kudos if you liked my post

Manager
Manager
User avatar
Joined: 12 Jan 2013
Posts: 244
Followers: 4

Kudos [?]: 58 [0], given: 47

GMAT ToolKit User
Re: Root(80)+root(125) [#permalink]

Show Tags

New post 18 Dec 2013, 14:04
Bunuel wrote:
\(\sqrt{80}+\sqrt{125} =\)

(A) \(9\sqrt{5}\)
(B) \(20\sqrt{5}\)
(C) \(41\sqrt{5}\)
(D) \(\sqrt{205}\)
(E) 100

Practice Questions
Question: 52
Page: 159
Difficulty: 600



The only thing I know is that the answer is just under 24.. And it is definitely not D since D falls between 14 and 15.. And it's clearly not E. And out of the 3 left, B and C are waay too high above 24, and I figured sqrrt of 5 is around "2.something" so A made most sense.

Clearly this approach is very shaky but this time it worked.
Manager
Manager
avatar
Joined: 13 Feb 2011
Posts: 104
Followers: 0

Kudos [?]: 20 [0], given: 3357

GMAT ToolKit User
Root(80)+root(125) [#permalink]

Show Tags

New post 20 Aug 2014, 23:32
\(\sqrt{80}\) is approx. 9 and \(\sqrt{125}\) is approx. 11 so the answer should be close to 20. Choice A is the closest.
Manager
Manager
avatar
Joined: 26 Feb 2015
Posts: 127
Followers: 0

Kudos [?]: 24 [0], given: 43

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 05 Mar 2015, 07:51
I see this question is from a subcategory called "Practice Questions", where can I find that sub?
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 34038
Followers: 6080

Kudos [?]: 76383 [0], given: 9973

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 05 Mar 2015, 07:58
Expert's post
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 10587
Followers: 495

Kudos [?]: 129 [0], given: 0

Premium Member
Re: Root(80)+root(125) [#permalink]

Show Tags

New post 15 Mar 2016, 06:26
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

Manager
Manager
User avatar
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 186
Location: United States (CA)
Followers: 4

Kudos [?]: 29 [0], given: 0

Re: Root(80)+root(125) [#permalink]

Show Tags

New post 04 May 2016, 10:03
Bunuel wrote:
\(\sqrt{80}+\sqrt{125} =\)

(A) \(9\sqrt{5}\)
(B) \(20\sqrt{5}\)
(C) \(41\sqrt{5}\)
(D) \(\sqrt{205}\)
(E) 100



Solution:

To solve the problem we must simplify the radicals. Radicals should be simplified whenever possible. Since the square root of a perfect square produces integers, it will often be helpful to locate and simplify perfect squares within a radical expression. Thus, we first locate the perfect squares that divide evenly into 80 and 125, making the simplification of each radical straightforward.

√80 = √16 x √5 = 4√5

√125 = √25 x √5 = 5√5

Now we can add these two results together. Remember to keep the value inside the radical constant and add together the values on the outside.

4√5 + 5√5 = 9√5

The answer is A.
_________________

Image
Jeffrey Miller
Scott Woodbury-Stewart
Founder and CEO

Math Forum Moderator
User avatar
Status: Moving Towards Perfection Now
Joined: 11 Jun 2011
Posts: 1158
Location: India
Concentration: International Business, Finance
Schools: ISB '18
WE: Corporate Finance (Commercial Banking)
Followers: 31

Kudos [?]: 274 [0], given: 198

GMAT ToolKit User Premium Member CAT Tests
Root(80)+root(125) [#permalink]

Show Tags

New post 04 May 2016, 10:19
Bunuel wrote:
\(\sqrt{80}+\sqrt{125} =\)

(A) \(9\sqrt{5}\)
(B) \(20\sqrt{5}\)
(C) \(41\sqrt{5}\)
(D) \(\sqrt{205}\)
(E) 100

Practice Questions
Question: 52
Page: 159
Difficulty: 600


\(\sqrt{80}+\sqrt{125} =\) \(4\sqrt{5}+5\sqrt{5}\) = \(9\sqrt{5}\)

Answer will be (A)
_________________

Abhishek....

Root(80)+root(125)   [#permalink] 04 May 2016, 10:19
Display posts from previous: Sort by

Root(80)+root(125)

  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 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®.