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

 It is currently 17 Feb 2019, 08:02

### 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

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

## Events & Promotions

###### Events & Promotions in February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT Algebra Webinar

February 17, 2019

February 17, 2019

07:00 AM PST

09:00 AM PST

Attend this Free Algebra Webinar and learn how to master Inequalities and Absolute Value problems on GMAT.
• ### Valentine's day SALE is on! 25% off.

February 18, 2019

February 18, 2019

10:00 PM PST

11:00 PM PST

We don’t care what your relationship status this year - we love you just the way you are. AND we want you to crush the GMAT!

# If x and y are positive integers such that x > y and the least common

Author Message
Manager
Joined: 13 May 2017
Posts: 103
Location: Finland
Concentration: Accounting, Entrepreneurship
GMAT 1: 530 Q42 V22
GPA: 3.14
WE: Account Management (Entertainment and Sports)
If x and y are positive integers such that x > y and the least common  [#permalink]

### Show Tags

09 Oct 2018, 04:00
1
2
00:00

Difficulty:

45% (medium)

Question Stats:

66% (01:57) correct 34% (01:22) wrong based on 41 sessions

### HideShow timer Statistics

If x and y are positive integers such that x > y and the least common multiple and greatest common divisor of the two integers are 36 and 6 respectively, what is the value of x – y?

(1) x = 18
(2) x + y = 30
examPAL Representative
Joined: 07 Dec 2017
Posts: 885
Re: If x and y are positive integers such that x > y and the least common  [#permalink]

### Show Tags

09 Oct 2018, 05:10
rencsee wrote:
If x and y are positive integers such that x > y and the least common multiple and greatest common divisor of the two integers are 36 and 6 respectively, what is the value of x – y?

(1) x = 18
(2) x + y = 30

Let's start by making a list of all the possible numbers:
numbers whose have 36 as a multiple: 1,2,3,4,6,9,12,18, 36
numbers whose have 6 as a divisor: 6, 12, 18, 24, 30, 36

Therefore, we have only two options for x and y: x=36,y=6 and x=18, y=12
both (1) and (2) separately tell us that of these two options, it must be x=18, y=12, therefore x=y = 6. Each statement on its own is sufficient! answer D.
_________________

Whatever your relationship status this year - we love you just the way you are. AND we want you to crush the GMAT!

So, here’s a Valentine’s Day gift for you:

Save 25% on all GMAT courses

Act quick. Because like some romances, this deal won't last forever

Intern
Joined: 31 Oct 2017
Posts: 1
Re: If x and y are positive integers such that x > y and the least common  [#permalink]

### Show Tags

15 Oct 2018, 20:18
Not sure why statement A is correct

Posted from my mobile device
Manager
Joined: 13 May 2017
Posts: 103
Location: Finland
Concentration: Accounting, Entrepreneurship
GMAT 1: 530 Q42 V22
GPA: 3.14
WE: Account Management (Entertainment and Sports)
Re: If x and y are positive integers such that x > y and the least common  [#permalink]

### Show Tags

15 Oct 2018, 21:16
MJ1993 wrote:
Not sure why statement A is correct

Posted from my mobile device

Hi MJ1993,

If you know that $$x=18=2*3^2$$, you can figure y from LCM and GCD.

$$LCM=36= 2^2*3^2$$
GCD= 6 = 2*3
$$x= 2*3^2$$
$$y= 2^2*3$$ <-- this is what left

Also, there is a little rule worth to memorize in the LCM/GCD topic.

LCM of x and y * GCD of x and y= x*y
so in this case: 36*6=xy, if you know the value of x, you get y very fast
Manager
Joined: 17 May 2015
Posts: 249
Re: If x and y are positive integers such that x > y and the least common  [#permalink]

### Show Tags

15 Oct 2018, 21:29
1
MJ1993,

Let me explain.

Theory:
The product of LCM and GCD(HCF) of two numbers is equal to the product of two numbers. i.e.

$$LCM(x,y) \times HCF(x,y) = x \times y.$$

Now, consider the given question. we have the following information from the question stem:

LCM(x,y) = 36, GCD(x,y) = 6, and x > y.

Statement(1): x = 18. Using the above-mentioned formula, we can easily compute the value of y. Hence, sufficient to answer the question.

Statement(2): x+y = 30. We know $$xy = LCM(x,y) \times HCF(x,y) = 36 \times 6 = 216.$$

$$(x-y)^2 = (x+y)^2 - 4xy$$ . Hence, we can find the value of x-y. Sufficient.

Hope this helps.
Thanks.
Re: If x and y are positive integers such that x > y and the least common   [#permalink] 15 Oct 2018, 21:29
Display posts from previous: Sort by