If x + y is an integer, is y an integer?

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If x + y is an integer, is y an integer? [#permalink]

01 Mar 2012, 08:39

If x + y is an integer, is y an integer?

(1) x – y is an integer.
(2) x + 2y is an integer.

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Re: If x + y is an integer [#permalink]

01 Mar 2012, 08:44

I would say B..

Here is my solution:
1)
X + Y = int could mean 4.5+3.5= int and
X-Y = 4.5-3.5=int
so there is an exception for A - then i eliminate D

2) X-2Y=INT (this and X+y = int) only if all items are integers

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Re: If x + y is an integer [#permalink]

01 Mar 2012, 08:46

If x + y is an integer, is y an integer?

(1) x – y is an integer --> if x=y=0.5 then the answer to the question is NO but if x=y=1 then the answer to the question is YES. Not sufficient.

(2) x + 2y is an integer --> x+2y=(x+y)+y=integer. Since given that x+y=integer, then: integer+y=integer --> y=integer. Sufficient.

Answer: B.
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Re: If x + y is an integer, is y an integer? [#permalink]

01 Mar 2012, 08:58

if x+y = integer Is y integer?
1.5+0.5 = integer
2+1 = integer

a) x-y=integer
2-1 = integer
1.5-.5 = integer ---NS

b) x+2y = integer

1+2(0.5) = integer
1+2(3) = integer ---NS
a+b)
NS

E
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Re: If x + y is an integer, is y an integer? [#permalink]

01 Mar 2012, 09:01

GMATD11 wrote:

if x+y = integer Is y integer?
1.5+0.5 = integer
2+1 = integer

a) x-y=integer
2-1 = integer
1.5-.5 = integer ---NS

b) x+2y = integer

1+2(0.5) = integer
1+2(3) = integer ---NS
a+b)
NS

E

x=1 and y=0.5 violates given statement that x+y=integer.

Answer to the question is B, not E.
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Re: If x + y is an integer, is y an integer? [#permalink] 01 Mar 2012, 09:01

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If x + y is an integer, is y an integer?

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If x + y is an integer, is y an integer?

If x + y is an integer, is y an integer?

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