GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 14 Nov 2018, 14:24

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 in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • $450 Tuition Credit & Official CAT Packs FREE

     November 15, 2018

     November 15, 2018

     10:00 PM MST

     11:00 PM MST

    EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299)
  • Free GMAT Strategy Webinar

     November 17, 2018

     November 17, 2018

     07:00 AM PST

     09:00 AM PST

    Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

If x is the greatest common divisor of 90 and 18, and y is the least

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50585
If x is the greatest common divisor of 90 and 18, and y is the least  [#permalink]

Show Tags

New post 17 Oct 2018, 00:21
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

85% (01:16) correct 15% (01:48) wrong based on 52 sessions

HideShow timer Statistics

Intern
Intern
avatar
B
Joined: 17 Dec 2016
Posts: 20
CAT Tests
Re: If x is the greatest common divisor of 90 and 18, and y is the least  [#permalink]

Show Tags

New post 17 Oct 2018, 00:51
Finding x - GCD (90 ,18)
90 = 2 x \(3^2\) x 5
18 = 2 x \(3^2\)

--> x = 2 x \(3^2\) = 18

Finding y - LCM (51,34)
51 = 3 x 17
34 = 2 x 17

--> y = 2 x 3 x 17 = 102

--> x + y = 102 + 18 = 120

--> Option B is the answer

Let me know your thought. Thank you
PS Forum Moderator
User avatar
P
Status: It always seems impossible until it's done.
Joined: 16 Sep 2016
Posts: 368
GMAT 1: 740 Q50 V40
GMAT ToolKit User Premium Member Reviews Badge CAT Tests
Re: If x is the greatest common divisor of 90 and 18, and y is the least  [#permalink]

Show Tags

New post 17 Oct 2018, 00:52
Bunuel wrote:
If x is the greatest common divisor of 90 and 18, and y is the least common multiple of 51 and 34, then x + y =


A. 111
B. 120
C. 213
D. 222
E. 231


To find the GCD and LCM of two numbers always denote the numbers in the prime factorization form -

First pair:
\(18 = 2^1*3^2\)
\(90 = 2^1*3^2*5^1\)

To find GCD of these two numbers - find the common factors ( along with powers) : So GCD would be : \(2^1*3^2 = 18\)

Second pair:

\(51 = 3^1*17^1\)
\(34 = 2^1*17^1\)

So GCD is \(17^1 = 17\) and the LCM is (First number * Second number)/GCD = \(\frac{(3^1*17^1*2^1*17^1)}{17^1} =\)\(3*2*17\)

Hence the question is asking \(18 + 6*17 = 18 + 102 = 120\)

Hence Option (B) is our choice.

Regards,
Gladi
Director
Director
User avatar
V
Joined: 06 Jan 2015
Posts: 512
Location: India
Concentration: Operations, Finance
GPA: 3.35
WE: Information Technology (Computer Software)
Premium Member
Re: If x is the greatest common divisor of 90 and 18, and y is the least  [#permalink]

Show Tags

New post 17 Oct 2018, 00:55
Bunuel wrote:
If x is the greatest common divisor of 90 and 18, and y is the least common multiple of 51 and 34, then x + y =


A. 111
B. 120
C. 213
D. 222
E. 231


If x is the greatest common divisor of 90 and 18 then x=18

And y is the least common multiple of 51 and 34 then y=102

x+y = 18+102 = 120

Hence B
_________________

आत्मनॊ मोक्षार्थम् जगद्धिताय च

Resource: GMATPrep RCs With Solution

Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4170
Location: United States (CA)
Re: If x is the greatest common divisor of 90 and 18, and y is the least  [#permalink]

Show Tags

New post 18 Oct 2018, 17:29
Bunuel wrote:
If x is the greatest common divisor of 90 and 18, and y is the least common multiple of 51 and 34, then x + y =


A. 111
B. 120
C. 213
D. 222
E. 231


Factoring 18 and 90, we get: 18 = 9 x 2 = 2 x 3^2 and 90 = 9 x 10 = 2 x 3^2 x 5

The GCF of 18 and 90 is 2 x 3^2 = 18. This is the value of x.

Factoring 51 and 34, we get: 51 = 3 x 17 and 34 = 2 x 17

The LCM of 51 and 34 is 17 x 2 x 3 = 102. This is the value of y.

Thus, the sum of x and y is 18 + 102 = 120.

Answer: B
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

GMAT Club Bot
Re: If x is the greatest common divisor of 90 and 18, and y is the least &nbs [#permalink] 18 Oct 2018, 17:29
Display posts from previous: Sort by

If x is the greatest common divisor of 90 and 18, and y is the least

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.