Oct 15 12:00 PM PDT  01:00 PM PDT Join this live GMAT class with GMAT Ninja to learn to conquer your fears of long, kooky GMAT questions. Oct 16 08:00 PM PDT  09:00 PM PDT EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299) Oct 19 07:00 AM PDT  09:00 AM PDT Does GMAT RC seem like an uphill battle? eGMAT is conducting a free webinar to help you learn reading strategies that can enable you to solve 700+ level RC questions with at least 90% accuracy in less than 10 days. Sat., Oct 19th at 7 am PDT Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score. Oct 22 08:00 PM PDT  09:00 PM PDT On Demand for $79. For a score of 4951 (from current actual score of 40+) AllInOne Standard & 700+ Level Questions (150 questions)
Author 
Message 
TAGS:

Hide Tags

Senior Manager
Joined: 30 Nov 2008
Posts: 421
Schools: Fuqua

If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
09 Mar 2009, 21:12
Question Stats:
61% (01:38) correct 39% (01:42) wrong based on 590 sessions
HideShow timer Statistics
If x is a positive integer, what is the least common multiple of x, 6 and 9? (1) The least common multiple of x and 6 is 30. (2) The least common multiple of x and 9 is 45.
Official Answer and Stats are available only to registered users. Register/ Login.




CEO
Joined: 17 Nov 2007
Posts: 3077
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth)  Class of 2011

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
10 Mar 2009, 03:57
GMAT TIGER wrote: 1) The least common multiple of x and 6 is 30: x could be 5, 10, 15 or 30. nsf. LCM(5,6,9)=90; LCM(10,6,9)=90; LCM(15,6,9)=90; LCM(30,6,9)=90; Sufficient GMAT TIGER wrote: 2) The least common mutiple of x and 9 is 45: x is 5, 15, or 45. nsf. the same. Sufficient Hey, guys, is it rule? LCM(a,b,c)=LCM(LCM(a,b),c) ? If yes, we can use it: 1) LCM(x,6,9) = LCM(30,9)=90 2) LCM(x,6,9) = LCM(45,6)=90 D
_________________
HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android)  The OFFICIAL GMAT CLUB PREP APP, a musthave app especially if you aim at 700+  Limited GMAT/GRE Math tutoring in Chicago




Senior Manager
Joined: 30 Nov 2008
Posts: 421
Schools: Fuqua

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
10 Mar 2009, 11:11
walker wrote: GMAT TIGER wrote: 1) The least common multiple of x and 6 is 30: x could be 5, 10, 15 or 30. nsf. LCM(5,6,9)=90; LCM(10,6,9)=90; LCM(15,6,9)=90; LCM(30,6,9)=90; Sufficient GMAT TIGER wrote: 2) The least common mutiple of x and 9 is 45: x is 5, 15, or 45. nsf. the same. Sufficient Hey, guys, is it rule? LCM(a,b,c)=LCM(LCM(a,b),c) ? If yes, we can use it: 1) LCM(x,6,9) = LCM(30,9)=90 2) LCM(x,6,9) = LCM(45,6)=90 D Exactly Walker, this is the short cut rule. LCM(a,b,c)=LCM(LCM(a,b),c). From stmt1, it LCM of 2 numbers(x,6) is given as 30. So LCM 3 numbers is LCM(30,9). Sufficient. From stmt2, again same explanation as stmt1. Initially I tried to find what is x from stmt 1 and then find the LCM of 3 numbers. THis is time consuming when the ans can be picked in less than 30 sec. I raised this question, since I wanted to know in how ways can people solve the question. As GMAT TIGER did, trying to find the x value rather than finding the LCM. No offense, just analysing where all there are possibilities that things can go wrong and that we should be cautious.




SVP
Joined: 29 Aug 2007
Posts: 1978

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
09 Mar 2009, 22:07
mrsmarthi wrote: If X is an integer, what is the Least Common Multiple of x, 6 and 9. 1) The least common multiple of x and 6 is 30 2) The least common mutiple of x and 9 is 45. I know the question is simple, but wanted to see in how many ways can this be answered(ofcourse correctly). DS is about logical solving. Lets get the ball rolling. 1. I guess I did it recently. 1) The least common multiple of x and 6 is 30: x could be 5, 10, 15 or 30. nsf. 2) The least common mutiple of x and 9 is 45: x is 5, 15, or 45. nsf. togather x = 5 and 15 suffff.... C.
_________________
Verbal: http://gmatclub.com/forum/newtotheverbalforumpleasereadthisfirst77546.html Math: http://gmatclub.com/forum/newtothemathforumpleasereadthisfirst77764.html Gmat: http://gmatclub.com/forum/everythingyouneedtoprepareforthegmatrevised77983.html
GT



Senior Manager
Joined: 30 Nov 2008
Posts: 421
Schools: Fuqua

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
09 Mar 2009, 22:31
GMAT TIGER Hum......Do you want to give another try?



Senior Manager
Joined: 25 Oct 2006
Posts: 465

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
14 Mar 2009, 06:52
Thanks to mrsmarthi and walker.....
_________________
If You're Not Living On The Edge, You're Taking Up Too Much Space



BSchool Moderator
Joined: 28 May 2012
Posts: 96
Location: India
Concentration: General Management, Strategy
GPA: 3.33
WE: Information Technology (Retail)

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
28 Sep 2012, 12:11
mrsmarthi wrote: If X is an integer, what is the Least Common Multiple of x,6 and 9. 1) The least common multiple of x and 6 is 30 2) The least common mutiple of x and 9 is 45. I know the question is simple, but wanted to see in how many ways can this be answered(ofcourse correctly). DS is about logical solving. Lets get the ball rolling. 1) the LCM of x and 6 is 30. That means you need to find the LCM of 30 and 9 > sufficient 2) LCM of x and 9 is 45 . you need to find out the LCM of 45 and 9 .  > sufficient . Answer D
_________________
You want something, go get it . Period !



Manager
Joined: 07 Apr 2014
Posts: 101

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
06 Sep 2014, 05:10
mrsmarthi wrote: If x is a positive integer, what is the least common multiple of x, 6 and 9?
(1) The least common multiple of x and 6 is 30. (2) The least common multiple of x and 9 is 45. from question : 6 2*3 9 3*3 x  prime factor of x 1. LCM(X,6) = 30 6 2,3 ; x can be 5  5 , 10  2*5 , 15 3*5 , 30 2*3*5... i.e x = 5 or 10 or 30 or 15 ... for all value of x  LCM (x,6,9)  90. 2. LCM(x, 9)=45 ; 9 3, 3 x can be 5 or 15 or 45 .... for all value of x  LCM (x,6,9)  90. hence D..



Intern
Joined: 12 Dec 2015
Posts: 16

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
18 Mar 2016, 11:51
First, find LCM of 9 and 6 = 18, and then find LCM of:
(I) 18 and 30 = 90, Suff (II) 18 and 45= 90, Suff
Answer D



Director
Joined: 26 Oct 2016
Posts: 614
Location: United States
Concentration: Marketing, International Business
GPA: 4
WE: Education (Education)

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
29 Jan 2017, 22:53
statement (1): the least common multiple of x and (2)(3) is (2)(3)(5). this means: we KNOW x contains exactly one 5, because otherwise that 5 wouldn't be in the lcm. x MAY contain a 2, a 3, both, or neither; any of these possibilities would yield the (2)(3) in the lcm. note that x cannot contain more than one 2 or 3, as those powers would then go into the lcm. x cannot contain any other primes, because those primes would have to appear in the lcm, and they don't. given these facts, you know that the lcm of x, (3)(2), and (3^2) is (2)(3^2)(5). if you don't see why right away, run through the possibilities.  statement (2): use the same kind of analysis as that used for statement (1). the lcm of x and (3^2) is (3^2)(5). therefore, we KNOW that x contains exactly one 5. x MAY contain no, one, or two 3's. x CANNOT contain any other primes. same sort of reasoning used above > the lcm must be (2)(3^2)(5); sufficient Hence D.
_________________
Thanks & Regards, Anaira Mitch



Intern
Joined: 18 Nov 2016
Posts: 41

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
03 Sep 2017, 09:09
mrsmarthi wrote: walker wrote: GMAT TIGER wrote: 1) The least common multiple of x and 6 is 30: x could be 5, 10, 15 or 30. nsf. LCM(5,6,9)=90; LCM(10,6,9)=90; LCM(15,6,9)=90; LCM(30,6,9)=90; Sufficient GMAT TIGER wrote: 2) The least common mutiple of x and 9 is 45: x is 5, 15, or 45. nsf. the same. Sufficient Hey, guys, is it rule? LCM(a,b,c)=LCM(LCM(a,b),c) ? If yes, we can use it: 1) LCM(x,6,9) = LCM(30,9)=90 2) LCM(x,6,9) = LCM(45,6)=90 D Exactly Walker, this is the short cut rule. LCM(a,b,c)=LCM(LCM(a,b),c). Does anyone have an article I could go to in order to learn more about this? mrsmarthi, walker



Senior Manager
Status: love the club...
Joined: 24 Mar 2015
Posts: 269

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
18 Sep 2017, 09:03
mrsmarthi wrote: If x is a positive integer, what is the least common multiple of x, 6 and 9?
(1) The least common multiple of x and 6 is 30. (2) The least common multiple of x and 9 is 45. hi LCM of x, 6, 9 is the same as the LCM of (x, 6) and 9.. statement 1 provides the LCM of (x, 6) sufficient .... in the same line of reasoning, LCM of x, 6, 9 is the same as the LCM of ( x, 9) and 6... statement 2 provides the LCM of (x, 9) sufficient... D cheers, if this helps ...



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2817

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
16 May 2018, 11:01
mrsmarthi wrote: If x is a positive integer, what is the least common multiple of x, 6 and 9?
(1) The least common multiple of x and 6 is 30. (2) The least common multiple of x and 9 is 45. We are given that x is a positive integer and need to determine the LCM of x, 6, and 9. If we can determine the value of x, then we can determine the LCM of x, 6, and 9. Statement One Alone: The least common multiple of x and 6 is 30. Using the information in statement one, we see that x can be 5 since LCM(5, 6) = 30. However, x can be also 10, 15, or 30; any of these values of x would also make LCM(x, 6) = 30. This may seem insufficient to answer the question, but let’s determine the LCM of x, 6 and 9 using these values: If x = 5, LCM(5, 6, 9) = 90. If x = 10, LCM(10, 6, 9) = 90. If x = 15, LCM(15, 6, 9) = 90. If x = 30, LCM(30, 6, 9) = 90. Since the LCM of x, 6, and 9 is always 90 for all possible values of x, we see that statement one is sufficient to answer the question. Statement Two Alone: The least common multiple of x and 9 is 45. Using the information in statement two, we see that x can be 5 since LCM(5, 9) = 45. However, x can be also 15 or 45; any of these values of x would also make LCM(x, 9) = 45. This may seem insufficient to answer the question, but let’s determine the LCM of x, 6 and 9 using these values: If x = 5, LCM(5, 6, 9) = 90. If x = 15, LCM(15, 6, 9) = 90. If x = 45, LCM(45, 6, 9) = 90. Since the LCM of x, 6, and 9 is always 90 for all possible values of x, statement two alone is sufficient to answer the question. Note: Using either statement, we’ve not determined a unique value for x. However, regardless what the value x is, we’ve determined a unique value for the LCM of x, 6 and 9. Answer: D
_________________
5star rated online GMAT quant self study course See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews
If you find one of my posts helpful, please take a moment to click on the "Kudos" button.



Intern
Joined: 26 Apr 2017
Posts: 9

Re: If x is a positive integer, what is the least common multiple of x, 6
[#permalink]
Show Tags
27 Oct 2018, 22:45
Just use basic concept A. LCM(x,6,9) = LCM(30,9)=90 B. LCM(x,6,9) = LCM(45,6)=90 IMO D



NonHuman User
Joined: 09 Sep 2013
Posts: 13168

Re: 4 GMATPrep Qs
[#permalink]
Show Tags
20 Sep 2019, 03:44
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.
_________________










