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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
Bunuel, can you please provide the OE.

I think most of us are missing some important information or misinterpreting the information provided.

GMATinsight, what is your take on this question?
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
I think the answer is D.

Based on the 2 equations separately, Value for x and y is either x=1;y=0. Alternatively x=0;y=1.

In any case, xy=0. So both statements are sufficient.
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
visram04 wrote:
I think the answer is D.

Based on the 2 equations separately, Value for x and y is either x=1;y=0. Alternatively x=0;y=1.

In any case, xy=0. So both statements are sufficient.


You are missing the case when x=y=1. This will satisfy statement 1 as well.
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
Oh Yes right. I din't notice 1+1 is 1.

Then answer should be E, as x and y can be 0 or 1 or both 1. So xy could be 0 or 1.
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
visram04 wrote:
Oh Yes right. I din't notice 1+1 is 1.

Then answer should be E, as x and y can be 0 or 1 or both 1. So xy could be 0 or 1.


Not really. If you look at my solution above,

Statement 1, gives : x = 0 , y=1 or x=y=1

Statement 2 gives: x=1, y =0 or x=y=1.

Thus combining we get, x =y=1 (sufficient!) and C should thus be the answer.
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
I am getting the answer as E, how is the answer B ?
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
Expert Reply
Bunuel wrote:

The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defined in the table. What is the value of x*y ?

(1) (x*y) + y = 1
(2) (x*y) + x = 1

Kudos for a correct solution.

Attachment:
2015-07-28_0114.png


The answer should be C. It was a typo in the book.
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
Bunuel wrote:
Bunuel wrote:

The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defined in the table. What is the value of x*y ?

(1) (x*y) + y = 1
(2) (x*y) + x = 1

Kudos for a correct solution.

Attachment:
2015-07-28_0114.png


The answer should be C. It was a typo in the book.


Thanks Bunuel, although I did spend quite a bit of time on finding out why wasnt I getting the OA in the first place. Good question though!
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
This is simple. a*b is the 'and' function, a+b is the 'or' function. 'And' means both of them should be 1 for the value to be 1. 'Or' means either or both should be 1 for the result to be 1.

St.1: (x*y)+y = 1
=>x.y + y =1
=> y.(x+1)=1 (because x+1 = 1)
=>y.1 = 1
=> y=1

Similarly, from statement 2, x = 1

Combining the 2 statements, x.y = 1

Had the question been the value of x+y, the answer would have been D.
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Re: The operators ‘*’ and ‘+’ operate only on the numbers 0 and 1 as defin [#permalink]
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