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

It is currently 18 Apr 2014, 07:41

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

For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,0

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
Joined: 12 Dec 2012
Posts: 230
Concentration: Leadership, Marketing
GMAT 1: 540 Q36 V28
GMAT 2: 550 Q39 V27
GMAT 3: 620 Q42 V33
GPA: 2.82
WE: Human Resources (Health Care)
Followers: 2

Kudos [?]: 36 [0], given: 181

For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,0 [#permalink] New post 16 Mar 2013, 09:01
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

61% (02:26) correct 38% (02:10) wrong based on 59 sessions
For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,000 and x + y + z = 15, what is the value of xy/z?

(A) undefined
(B) 0
(C) 3
(D) 5
(E) 15

http://www.veritasprep.com/blog/2010/09 ... -opponent/
[Reveal] Spoiler: OA

_________________

My RC Recipe
http://gmatclub.com/forum/the-rc-recipe-149577.html

My Problem Takeaway Template
http://gmatclub.com/forum/the-simplest-problem-takeaway-template-150646.html


Last edited by Bunuel on 17 Mar 2013, 00:05, edited 1 time in total.
Renamed the topic and edited the question.
Veritas Prep GMAT Discount CodesKnewton GMAT Discount CodesManhattan GMAT Discount Codes
1 KUDOS received
Director
Director
Status:
Joined: 24 Jul 2011
Posts: 525
GMAT 1: 780 Q51 V48
GRE 1: 1540 Q800 V740
Followers: 54

Kudos [?]: 232 [1] , given: 9

Re: Your Opponent is the exponent [#permalink] New post 16 Mar 2013, 09:27
1
This post received
KUDOS
3,276,800,000 = 32,768 x 100,000 = 2^15 x 100,000 = 2^15 x 5^5 x 2^5 = 2^20 x 5^5

Therefore x =0, y =10, z = 5

xy/z = 0

The answer is B. Although this detailed explanation has been provided, you can straightaway reach the answer by realizing that x=0 since the large number given does not have 3 as a factor, and so xy/z has to be 0.
_________________

Free profile evaluation by top b-school alumni: email us at info@gyanone.com
Personalized 1-on-1 GMAT coaching: www.gyanone.com/1-on-1-gmat/

Manager
Manager
Joined: 12 Dec 2012
Posts: 230
Concentration: Leadership, Marketing
GMAT 1: 540 Q36 V28
GMAT 2: 550 Q39 V27
GMAT 3: 620 Q42 V33
GPA: 2.82
WE: Human Resources (Health Care)
Followers: 2

Kudos [?]: 36 [0], given: 181

Re: Your Opponent is the exponent [#permalink] New post 16 Mar 2013, 10:22
GyanOne wrote:
3,276,800,000 = 32,768 x 100,000 = 2^15 x 100,000 = 2^15 x 5^5 x 2^5 = 2^20 x 5^5

Therefore x =0, y =10, z = 5

xy/z = 0

The answer is B. Although this detailed explanation has been provided, you can straightaway reach the answer by realizing that x=0 since the large number given does not have 3 as a factor, and so xy/z has to be 0.


Thanks :-D but how did you get that the big number = 2^15? and why the absence of 3 from the factors would lead the fraction to be = zero?
_________________

My RC Recipe
http://gmatclub.com/forum/the-rc-recipe-149577.html

My Problem Takeaway Template
http://gmatclub.com/forum/the-simplest-problem-takeaway-template-150646.html

1 KUDOS received
Intern
Intern
Joined: 03 Sep 2011
Posts: 18
Followers: 0

Kudos [?]: 3 [1] , given: 4

GMAT ToolKit User
Re: Your Opponent is the exponent [#permalink] New post 16 Mar 2013, 14:02
1
This post received
KUDOS
If we know that 3,276,800,000 is not divisible by 3 (which by the way you can quickly test by adding the digits of the number together and seeing whether they are divisble by 3) , this implies that when it is expressed in the form (3^x) (4^y) (5^z) the x=0. Hence xy/z =0
Concerning the 2^15, either you know the powers of 2 or you don't. This one is indeed very high so it seems unlikely to know it by heart. But if you divide 32768 by 8 for example you land on 4096 (which is 2^12) so you eventually figure out that it's 2^15. But again, this was not necessary in order to solve the question.
Intern
Intern
Joined: 21 Aug 2013
Posts: 10
Followers: 0

Kudos [?]: 0 [0], given: 169

Re: For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,0 [#permalink] New post 07 Sep 2013, 12:48
'x' is the easiest to check here.. just add the digits of the number, sum is 26, thus this is not a multiple of 3.. since 'x' is an integer it must be '0'..
now neither of 'y' or 'z' could be '0' because just by looking we see that this number has trailing zeroes so it must have both 2 and 5...

so simply since 'x' is '0' the given solution is '0'. Hence B
Senior Manager
Senior Manager
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 395
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 1

Kudos [?]: 69 [0], given: 153

Re: For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,0 [#permalink] New post 26 Feb 2014, 20:44
Jut observe the RHS, 3,276,800,000 can be written as 32768 x 100000

32768 is not divisible by 3, so x = 0

xy/z = 0 = Answer = B; no need to calculate the rest
_________________

Kindly press "Kudos" to appreciate

Re: For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,0   [#permalink] 26 Feb 2014, 20:44
    Similar topics Author Replies Last post
Similar
Topics:
New posts If x, y, and z are positive integers and 3x = 4y = 7z, then Juan8 2 09 May 2005, 23:06
New posts If x, y and z are positive integers and 3x=4y=7z, then the SimaQ 2 04 Jun 2006, 02:50
New posts If x, y, and z are positive integers and 3x=4y=7z, then the chrismeiyu 3 06 Sep 2006, 15:37
New posts If x, y, and z are positive integers and 3x = 4y = 7z, then SimaQ 7 19 Oct 2006, 09:33
New posts 8x+4y+5z=3 x,y,z are positive numbers what is x? (1)4y is an pmenon 5 10 Jan 2009, 07:30
Display posts from previous: Sort by

For integers x, y, and z, if (3^x) (4^y) (5^z) = 3,276,800,0

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| 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®.