Last visit was: 31 Aug 2024, 18:43 It is currently 31 Aug 2024, 18:43
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 Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 10133
Own Kudos [?]: 17227 [15]
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Send PM
Current Student
Joined: 13 Apr 2015
Posts: 1425
Own Kudos [?]: 4637 [1]
Given Kudos: 1228
Location: India
Send PM
avatar
Intern
Intern
Joined: 14 Mar 2014
Posts: 13
Own Kudos [?]: 5 [1]
Given Kudos: 41
Schools: HBS '17
Send PM
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11518
Own Kudos [?]: 35683 [1]
Given Kudos: 333
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
1
Bookmarks
Expert Reply
Lastlap2016 wrote:
Vyshak wrote:
St1: x+y+z is a multiple of 3.
If x = 1, y = 1, z = 1 then xyz is not a multiple of 3.
If x = 3, y = 3, z = 3 then xyz is a multiple of 3
Not Sufficient

St2: x, y, z are consecutive --> Product of three consecutive integers will always be a multiple of 3.
Sufficient

Answer: B



i think answer should be D . coz XYZ appears to be a three digit number rather than product of three digits IMO.


Hi,
whenever xyz is written, it means product of x, y and z..
If xyz is 3-digit nnumber, it will be mentioned..

In that the case would be-
If x, y, z are integers and xyz is a 3-digit number, is xyz a multiple of 3?
OR If x, y, z are integers, is xyz, a 3-digit number, a multiple of 3?
User avatar
Intern
Intern
Joined: 06 May 2016
Posts: 11
Own Kudos [?]: 15 [1]
Given Kudos: 5
WE:Education (Education)
Send PM
If x, y, z are integers, is xyz a multiple of 3? [#permalink]
1
Kudos
I was confused for a moment, I missed that 0 is a multiple of any number.
I chose (C) thinking we needed Stmnt 1 to tell us that X,Y,Z is positive (which it in fact does not).

Take-away for me is to differentiate between multiple (which can be 0, -3, -6 etc too) and positive multiple (3,6,9)
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 10133
Own Kudos [?]: 17227 [0]
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
Expert Reply
If we multiply the consecutive 3 integers, the outcome is always a multiple of 6. The condition 2) gives an answer that is always yes and the condition is sufficient. Hence, the correct answer is B. The condition is not sufficient because it gives 2 answers, 1+2+3 yes and 2+2+2 no.

- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
Alum
Joined: 12 Aug 2015
Posts: 2268
Own Kudos [?]: 3224 [0]
Given Kudos: 893
GRE 1: Q169 V154
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
Let x,y,z => 1,1,1 and x,y,z => 3,3,3 => statement 1 is insuff
now using the rule => "THE PRODUCT OF N CONSECUTIVES IS ALWAYS DIVISIBLE BY N! " => xyz=> divisible by 6.
((((Hence using the factor foundation rule => its clearly divisible by 3)))

Smash that B
avatar
Intern
Intern
Joined: 23 Jun 2016
Posts: 34
Own Kudos [?]: 10 [0]
Given Kudos: 13
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
Not sure if this makes sense. The problem doesn't state the xyz are positive integers. So if x = -1, y = 0, z = 1 they would be considered consecutive but statement 2 would be insufficient. So the answer should be C
Alum
Joined: 12 Aug 2015
Posts: 2268
Own Kudos [?]: 3224 [0]
Given Kudos: 893
GRE 1: Q169 V154
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
Akuthiala wrote:
Not sure if this makes sense. The problem doesn't state the xyz are positive integers. So if x = -1, y = 0, z = 1 they would be considered consecutive but statement 2 would be insufficient. So the answer should be C


You sure mate?
Here the product = -1*0*1=0
=> ZERO is divisible By every Integer hence xyz is divisble by 3 here too :)
Suff
The generalised rule => PRODUCT of n consecutive integers is always divisible by n! (which is n factorial)

I hope it helps with your query
Stone Cold
avatar
Intern
Intern
Joined: 12 Oct 2016
Posts: 2
Own Kudos [?]: 1 [0]
Given Kudos: 43
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
Answer should be D

1) 1 + 1 +1 = 3 then 111 is also a multiple of 3 111 = 37 * 3
2 + 2 + 2 = 6 then 222 is a multiple of 3 222 = 74 * 3

2) since x y z are consecutive then cuz will be multiple of 3
7 8 9
Manager
Manager
Joined: 06 Jun 2013
Posts: 120
Own Kudos [?]: 37 [0]
Given Kudos: 339
Location: India
Concentration: Finance, Economics
Schools: Tuck
GMAT 1: 640 Q49 V30
GPA: 3.6
WE:Engineering (Computer Software)
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
if x, y , z were three distinct positive integers, what would have been the answer ?

in this case, option would have been D.
Current Student
Joined: 07 May 2020
Posts: 57
Own Kudos [?]: 21 [0]
Given Kudos: 32
Location: United States
Schools: LBS '23 (A)
GRE 1: Q165 V159
GPA: 3.85
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
stonecold - I'm just a few years late on this but I have a burning query. I see that zero is divisible by 3 but wouldn't that make zero a factor of 3 and not a multiple of 3??
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11518
Own Kudos [?]: 35683 [2]
Given Kudos: 333
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
2
Kudos
Expert Reply
LaurenGol wrote:
stonecold - I'm just a few years late on this but I have a burning query. I see that zero is divisible by 3 but wouldn't that make zero a factor of 3 and not a multiple of 3??



0=3*0, so 0 is a multiple of 3, same way as 6 is because 6=3*2.

OR

Does 3 come in 0s table ...No, so 3 is not a multiple of 0.
Does 0 come in 3s table if we include negative integers too... ...-6,-3,0,3,6..
Yes, 0 is a multiple of 3 and every number.
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 34662
Own Kudos [?]: 872 [0]
Given Kudos: 0
Send PM
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
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.
GMAT Club Bot
Re: If x, y, z are integers, is xyz a multiple of 3? [#permalink]
Moderator:
Math Expert
95291 posts