text: Find all School-related info fast with the new School-Specific MBA Forum
  
   It is currently 04 Jul 2015, 12:45
  
  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 June
  Open Detailed Calendar
  
  Is x^2y^4 an integer divisible by 9 ? (1) x is an integer
  
  Author Message
  TAGS:
  Retired Moderator
  Joined: 18 Jul 2008
  Posts: 994
  Followers: 10
  
  Kudos [?]: 110 [0], given: 5
  
  Is x^2y^4 an integer divisible by 9 ? (1) x is an integer [#permalink]  11 Mar 2009, 17:45
  00:00
  
  Difficulty:
  
  (N/A)
  
  Question Stats:
  
  0% (00:00) correct 0% (00:00) wrong based on 0 sessions
  Is x^2y^4 an integer divisible by 9 ?
  
  (1) x is an integer divisible by 3
  (2) xy is an integer divisible by 9
  Senior Manager
  Joined: 08 Jan 2009
  Posts: 329
  Followers: 2
  
  Kudos [?]: 91 [0], given: 5
  
  Re: DS: Divisibility [#permalink]  11 Mar 2009, 18:56
  Given:
  
  Is x^2 * y^4 divisible by 9?
  
  1. x = 3k x^2 = 9k^2 therefore sufficient
  
  2. xy = 9K.
  
  x is a mutiple of 9 or y is a multiple of 9 or x and y( x =3a, y=3b) will contain factors of 9.
  
  On all cases it is divisible. Sufficient.
  
  Ans: D
  Intern
  Joined: 28 Feb 2009
  Posts: 31
  Followers: 0
  
  Kudos [?]: 3 [0], given: 0
  
  Re: DS: Divisibility [#permalink]  11 Mar 2009, 23:38
  I would say D since:
  
  (1) x being divisible by 3 and then being squared will ensure that there are two factors of three, which means x the any expression including x^2 will be divisible by 9
  
  (2) if xy is divisible by 9, then raising it to the fourth will ensure that there are factors to make it divisible 4 times...
  
  Is this a reasonable explanation?
  _________________
  
  Helpful GMAT Resources: GMAT Club | Official Guide GMAT Prep | MBA.com Prep | Free GMAT Prep | GMAC
  
  SVP
  Joined: 04 May 2006
  Posts: 1936
  Schools: CBS, Kellogg
  Followers: 19
  
  Kudos [?]: 490 [0], given: 1
  
  Re: DS: Divisibility [#permalink]  12 Mar 2009, 00:15
  Is x^2y^4 an integer divisible by 9 ?
  
  (1) x is an integer divisible by 3
  (2) xy is an integer divisible by 9
  
  E
  
  1. says nothing about y, Not suff
  1.1 x=3, y=1, OK x^2y^4 is an INTEGER divisible by 9
  1.2 x=3, but y= 1/2 so y=1/2^4 --> x^2y^4 can not be an integer divisible by 9
  
  2. Again, xy is an integer and x^2y^2 can be an integer but y^2 alone can not necessarily be integer, so x^y^4 are not necessarily be an integer divisible by 9! not suff
  
  1 and 2 combine, not suff too
  _________________
  Senior Manager
  Joined: 08 Nov 2008
  Posts: 307
  Followers: 2
  
  Kudos [?]: 86 [0], given: 7
  
  Re: DS: Divisibility [#permalink]  12 Mar 2009, 04:25
  Trap - qts force us to think Y as interger ..
  What if Y is 1.5 or .5 ??
  
  Agree with E .
  _________________
  
  "CEO in making"
  
  Retired Moderator
  Joined: 18 Jul 2008
  Posts: 994
  Followers: 10
  
  Kudos [?]: 110 [0], given: 5
  
  Re: DS: Divisibility [#permalink]  12 Mar 2009, 05:22
  The OA is E. good explanation guys.
  Senior Manager
  Joined: 08 Jan 2009
  Posts: 329
  Followers: 2
  
  Kudos [?]: 91 [0], given: 5
  
  Re: DS: Divisibility [#permalink]  13 Mar 2009, 08:06
  Thank you Guys.
  
  i got my mistake.
  Re: DS: Divisibility   [#permalink] 13 Mar 2009, 08:06
  Similar topics Replies Last post
  Similar
  Topics:
  13 If x and y are integers and 4xy = x^2*y+4y, what is the 15 23 May 2012, 00:57
  Is x^2 = y^4/(y^4)^(1/2) ? 1 28 Jan 2012, 10:53
  22 Is x^2*y^4 an integer divisible by 9 ? 17 13 Sep 2010, 13:15
  Is x^2*y^4 divisible by 49? (1) x is an integer divisible by 14 20 Jan 2006, 14:14
  Is x^2*y^4 divisible by 49? (1) x is an integer 10 10 Jul 2005, 08:24
  Display posts from previous: Sort by
metadata: {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0}