|
Author |
Message |
|
TAGS:
|
|
|
Director
Joined: 06 Sep 2006
Posts: 749
Followers: 1
Kudos [?]:
8
[0], given: 0
|
If x and y are integers greater than 1, is x a multiple of [#permalink]
 22 Jul 2007, 21:18
Question Stats:
0% (00:00) correct
 0% (00:00) wrong based on 0 sessions
If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y.
Share your solutions guys, just not the answers!
|
|
|
|
|
|
|
Senior Manager
Joined: 04 Jun 2007
Posts: 357
Followers: 1
Kudos [?]:
9
[0], given: 0
|
Re: DS - number properties [#permalink]
22 Jul 2007, 21:38
asaf wrote: If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y.
Share your solutions guys, just not the answers!
A for me.
stmt 1: y*(3y+7) = x
or, 3y+7 = x/y
Since, 3y+7 must be an integer, so too must be x/y. Hence, x is a multiple of y. sufficient.
stmt 2: x*(x-1) = ky (k is some integer greater than 0)
This is not sufficient. e.g. x=3 and y=2; x=4 and y=2
|
|
|
|
|
|
Senior Manager
Joined: 28 Jun 2007
Posts: 464
Followers: 2
Kudos [?]:
5
[0], given: 0
|
I think E.
I cant share my solution because I couldn't solve this easily. 1 and 2 alone look insufficient. So I made an educated guess.
|
|
|
|
|
|
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5134
Location: Singapore
Followers: 9
Kudos [?]:
89
[0], given: 0
|
St1:
y(3y+7) = x
3y+7 = x/y
Since 3y + 7 must be integer, then x/y must be integer and x must be a multiple of y if x/y = integer.
St2:
x(x-1) = ym
(x/y)(x-1) = m
Since m is an integer, (x-1) is an integer then x/y must be an integer for the relationship to hold. So x must be a multiple of y.
Ans D
|
|
|
|
|
|
Senior Manager
Joined: 04 Jun 2007
Posts: 357
Followers: 1
Kudos [?]:
9
[0], given: 0
|
ywilfred wrote: St1:
y(3y+7) = x
3y+7 = x/y
Since 3y + 7 must be integer, then x/y must be integer and x must be a multiple of y if x/y = integer.
St2:
x(x-1) = ym
(x/y)(x-1) = m
Since m is an integer, (x-1) is an integer then x/y must be an integer for the relationship to hold. So x must be a multiple of y.
Ans D
I do not think statement 2 can be sufficient. (x-1) and not x may be a multiple of y.
|
|
|
|
|
|
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5134
Location: Singapore
Followers: 9
Kudos [?]:
89
[0], given: 0
|
sumande wrote: ywilfred wrote: St1:
y(3y+7) = x
3y+7 = x/y
Since 3y + 7 must be integer, then x/y must be integer and x must be a multiple of y if x/y = integer.
St2:
x(x-1) = ym
(x/y)(x-1) = m
Since m is an integer, (x-1) is an integer then x/y must be an integer for the relationship to hold. So x must be a multiple of y.
Ans D I do not think statement 2 can be sufficient. (x-1) and not x may be a multiple of y. yeah.. missed that point. Ouch! 
|
|
|
|
|
|
Director
Joined: 08 Jun 2007
Posts: 586
Followers: 1
Kudos [?]:
66
[0], given: 0
|
Re: DS - number properties [#permalink]
23 Jul 2007, 08:27
asaf wrote: If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y.
Share your solutions guys, just not the answers!
I am going with B .
1. y(3y +7 ) = x . I think it means y is a multiple of x and not as it is asked "is x a multiple of h?" So insufficient.
2. x(x-2) = ky . This proves x is a multiple of y .Sufficient
So B .
BTW , whats the OA ?
|
|
|
|
|
|
Senior Manager
Joined: 04 Jun 2007
Posts: 357
Followers: 1
Kudos [?]:
9
[0], given: 0
|
Re: DS - number properties [#permalink]
23 Jul 2007, 08:46
ashkrs wrote: asaf wrote: If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y.
Share your solutions guys, just not the answers! I am going with B . 1. y(3y +7 ) = x . I think it means y is a multiple of x and not as it is asked "is x a multiple of h?" So insufficient. 2. x(x-2) = ky . This proves x is a multiple of y .Sufficient So B . BTW , whats the OA ? The question clearly asks if "x is a multiple of y" !!
|
|
|
|
|
|
Director
Joined: 08 Jun 2007
Posts: 586
Followers: 1
Kudos [?]:
66
[0], given: 0
|
Re: DS - number properties [#permalink]
24 Jul 2007, 08:19
sumande wrote: ashkrs wrote: asaf wrote: If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y.
Share your solutions guys, just not the answers! I am going with B . 1. y(3y +7 ) = x . I think it means y is a multiple of x and not as it is asked "is x a multiple of h?" So insufficient. 2. x(x-2) = ky . This proves x is a multiple of y .Sufficient So B . BTW , whats the OA ? The question clearly asks if "x is a multiple of y" !! I think I am getting my terminology wrong. Please correct me .
If X is a multiple of Y .
I understand that as : if Y = 36 then X can be 1 2 3 4 6 12 18.
|
|
|
|
|
|
Intern
Joined: 12 Jun 2007
Posts: 20
Followers: 0
Kudos [?]:
0
[0], given: 0
|
Clear A.
x= y(3y+7) meaning x is a multiple of y.
|
|
|
|
|
|
Intern
Joined: 12 May 2007
Posts: 23
Followers: 0
Kudos [?]:
0
[0], given: 0
|
y*(3y+7)=x sufficient
x(x-1)= y ; this would mean that y is a multiple of x. it is not the question?
my answer A.
do you have official answer??
|
|
|
|
|
|
Senior Manager
Joined: 21 Jun 2006
Posts: 292
Followers: 1
Kudos [?]:
5
[0], given: 0
|
I say A
statment in A can be factorized into
y(3y+7)=x
3y+7 must be an integer as y >1 and int
B
x(x-1)=ky
where k is int
therefore, x = (k/x-1)y
k/x-1 need not be an integer
say if x =18, x-1 = 17 and k =5 then x is not a multiple of y
Hence INSIFF
|
|
|
|
|
|
Current Student
Joined: 28 Dec 2004
Posts: 3437
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 11
Kudos [?]:
135
[0], given: 2
|
If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y.
OK lets see...
x/y=N where N is an integer?
1) Y(3Y+7)=x; x/y= (3Y+7) we are told x and y are integers...therefor RHS is an integer...which inturn means RHS is an integer...therefore X is a multiple..sufficient..
2) x(x-1)=y/N ...we dont know if X or X-1 is the multiple of Y..therefore insufficient...
A it is..
|
|
|
|
|
|
Director
Joined: 26 Feb 2006
Posts: 919
Followers: 3
Kudos [?]:
28
[0], given: 0
|
Re: DS - number properties [#permalink]
25 Jul 2007, 09:57
asaf wrote: If x and y are integers greater than 1, is x a multiple of y?
1) 3y^2 + 7y = x
2) x^2 - x is a multiple of y
A too...........
from 1: 3y^2 + 7y = x
y (3y + 7) = x
in this case, 3y+7 is an integer. so x is a multiple of x.
from 2: x^2 - x = yk
x (x -1) = yk
x (x -1) = yk
k could be or could not be x or x-1. suppose, x = 4, x-1=3, k =1 and y = 12. in this case x is not a multiple of y. if x = 4, x-1 = 3, y = 3 and k =4, x is a multiple of y.
|
|
|
|
|
|
|
Re: DS - number properties
[#permalink]
25 Jul 2007, 09:57
|
|
|
|
|
|
|
|
|
Similar topics |
Author |
Replies |
Last post |
|
Similar
Topics:
|
 |
2
|
|
If x and y are integers greater than 1, is x a multiple of
|
themagiccarpet |
45 |
16 Nov 2005, 02:56 |
 |
|
|
if x and y are integrs greater than 1, is x a multiple of y
|
deep |
3 |
15 Nov 2006, 01:45 |
 |
1
|
 |
If x and y are both integers greater than 1, is x a multiple
|
chineseburned |
10 |
04 May 2008, 19:26 |
|
|
|
|
If x an y are integers greater than 1, is x a multiple of y?
|
mba9now |
3 |
29 Jul 2008, 21:10 |
|
|
6
|
|
If x and y are integers greater than 1, is x a multiple of y
|
enigma123 |
10 |
29 Jan 2012, 16:21 |
|
|
|
|
|
|
close
