Last visit was: 23 Jul 2024, 23:06 It is currently 23 Jul 2024, 23:06
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
SORT BY:
Date
Tags:
Show Tags
Hide Tags
Math Expert
Joined: 02 Sep 2009
Posts: 94589
Own Kudos [?]: 643423 [0]
Given Kudos: 86728
Send PM
Director
Director
Joined: 05 Mar 2015
Posts: 841
Own Kudos [?]: 879 [0]
Given Kudos: 45
Send PM
Senior Manager
Senior Manager
Joined: 15 Jan 2017
Posts: 257
Own Kudos [?]: 87 [0]
Given Kudos: 932
Send PM
Current Student
Joined: 09 Mar 2017
Posts: 82
Own Kudos [?]: 51 [1]
Given Kudos: 30
Location: Netherlands
Concentration: General Management, Finance
GMAT 1: 690 Q45 V40
GRE 1: Q168 V156
Send PM
Re: If j is an integer, is k an integer? [#permalink]
1
Kudos
Madhavi1990 wrote:
rohit8865 wrote:
Bunuel wrote:
If j is an integer, is k an integer?

(1) j – 2k is an integer.
(2) 5k – j is an integer.



let j=10
(1) then, if k=1 then yes
k=1/2 No ....insuff

(2) k=1 then yes
k=1/5 then No...insuff..

combined k must be ineteger....suff


Ans C


Questions asks if k is an integer? J is already integer. (it can be positive or negative).

A) is quite clear, its is INSUFFICIENT

in B if, k = 0.2 (which is 1/5) --> 5(0.2) - j (the integer) --> 1 - 2 = -1 there fore k is NOT integer.(is j is 2, 3, 4.. since answer is an integer, so answer can be negative or positive).
On the other hand, if k =1 --> then 5 - 4 (if j = 4) --> 1 or 5 - (-2) --> 7. Again K is Integer.
So both are INSUFFICIENT.
Hence E

How is C the answer? Could you give me a little detail into the solving? Thank you, it would be highly appreciated :)

Hi,

There is no single non-integer which can be multiplied by either 2 or 5, and still results in an integer. So since the number results in an integer when multiplied by either 2 or 5, it must be an integer. Hope this helps!



Sent from my SM-G935F using GMAT Club Forum mobile app
Manager
Manager
Joined: 25 May 2016
Posts: 79
Own Kudos [?]: 81 [1]
Given Kudos: 497
Location: Singapore
Concentration: Finance, General Management
GMAT 1: 620 Q46 V30
Send PM
Re: If j is an integer, is k an integer? [#permalink]
1
Kudos
(1) j-2k
k could be 1 or 1/2
Insufficient information

(2) 5k-j
If k=1 then yes
k=1/2 then insufficient information

combine them and we know k times 2 or k times 5 is an integer and therefore sufficient.
Option C
Manager
Manager
Joined: 17 Oct 2016
Posts: 226
Own Kudos [?]: 437 [0]
Given Kudos: 49
Location: India
Concentration: General Management, Healthcare
GPA: 3.05
WE:Pharmaceuticals (Health Care)
Send PM
If j is an integer, is k an integer? [#permalink]
1 and 2 alone are clearly not sufficient

Now, If we combine 1 and 2:

2K is an integer, and 5K is integer
for 5K to be integer, k = 0.2, 0.4, 0.6, 0.8, 1.0, 1.2....and so on...
but 2K cannot be an integer if k = 0.2, 0.4, 0.6, 0.8, 1.0, 1.2.

So K has to be an integer if 2k and 5k are integer.

1 and 2 combined are sufficient to answer the question
GMAT Club Bot
If j is an integer, is k an integer? [#permalink]
Moderator:
Math Expert
94589 posts