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

It is currently 20 Sep 2018, 04:34

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

a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?

  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: 49271
a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?  [#permalink]

Show Tags

New post 26 Jun 2018, 06:24
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

67% (02:02) correct 33% (01:33) wrong based on 57 sessions

HideShow timer Statistics

Intern
Intern
avatar
B
Joined: 27 Nov 2017
Posts: 1
Re: a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?  [#permalink]

Show Tags

New post 26 Jun 2018, 06:38
Starting with statement (2):

(2) b when prime factorized will be of the form (5)^s

This in insufficient on its own because it provides nothing to help us figure out what X could be.



Statement (1)
(1) 35 is a factor of a

This tells us that that A's prime factorization are at least one 5, and at least one 7.
Insufficient on its own because it tells us nothing about X. B could contain the 7 or X could contain the 7.



Together: It looks like we can solve it since we'd know that B is 5 raised to some power, leaving X with the factorization of 7.
C is our answer.
Manager
Manager
avatar
B
Joined: 09 Oct 2015
Posts: 222
a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?  [#permalink]

Show Tags

New post 26 Jun 2018, 07:06
quyanhle24 wrote:
Starting with statement (2):

(2) b when prime factorized will be of the form (5)^s

This in insufficient on its own because it provides nothing to help us figure out what X could be.



Statement (1)
(1) 35 is a factor of a

This tells us that that A's prime factorization are at least one 5, and at least one 7.
Insufficient on its own because it tells us nothing about X. B could contain the 7 or X could contain the 7.



Together: It looks like we can solve it since we'd know that B is 5 raised to some power, leaving X with the factorization of 7.
C is our answer.


Answer should be e, because even together if a is 35, and b is 5x5 then we would not have an integer, whereas we would with b as 5
Manager
Manager
User avatar
S
Joined: 28 Jul 2016
Posts: 95
Location: India
GMAT 1: 680 Q50 V32
GPA: 3.97
CAT Tests
Re: a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?  [#permalink]

Show Tags

New post 26 Jun 2018, 11:39
rahulkashyap wrote:
quyanhle24 wrote:
Starting with statement (2):

(2) b when prime factorized will be of the form (5)^s

This in insufficient on its own because it provides nothing to help us figure out what X could be.



Statement (1)
(1) 35 is a factor of a

This tells us that that A's prime factorization are at least one 5, and at least one 7.
Insufficient on its own because it tells us nothing about X. B could contain the 7 or X could contain the 7.



Together: It looks like we can solve it since we'd know that B is 5 raised to some power, leaving X with the factorization of 7.
C is our answer.


Answer should be e, because even together if a is 35, and b is 5x5 then we would not have an integer, whereas we would with b as 5

should be C as it mentions are all positive integers
_________________

Please give Kudos. Kudos encourage active discussions and help the community grow

Manager
Manager
avatar
B
Joined: 09 Oct 2015
Posts: 222
Re: a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?  [#permalink]

Show Tags

New post 26 Jun 2018, 18:46
Ans is c you're right

Posted from my mobile device
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6792
Re: a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?  [#permalink]

Show Tags

New post 26 Jun 2018, 19:33
a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?

(1) 35 is a factor of a
So ay is a multiple of 35 or 7, thus the right hand side bx also will be multiple of 7..
But it is possible that only b or only x or both b and x are multiple of 7
Insufficient

(2) b when prime factorized will be of the form (5)^s
Nothing about x
Insufficient

Combined
From statement I, b or x or both can be multiple of 7
But statement II tells us that b is multiple of only one prime number 5
So x has to be a multiple of 7
Sufficient

C
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Re: a, b, x and y are positive integers. If ay = bx, is 7 a factor of x? &nbs [#permalink] 26 Jun 2018, 19:33
Display posts from previous: Sort by

a, b, x and y are positive integers. If ay = bx, is 7 a factor of x?

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

Events & Promotions

PREV
NEXT


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®.