My answer is C
From statement 1
x y x*y (x*y) + y
0 1 0 1
1 1 1 1
Then when y = 0 the statement is not true anymore, therefore the value of x*y could be either 0 or 1
From statement 2
x y x*y (x*y) + x
1 0 0 1
1 1 1 1
Then when x = 0 the statement is not true anymore, therefore the value of x*y could be either 0 or 1
From statement 1 and 2, x=1 and y=1, therefore x*y=1
Thus the final answer is C
Functions
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Source: Beat The GMAT — Data Sufficiency |
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gmatmachoman
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I am getting C .
Lets start with st 2 :
(x*y) + x =1
case 1 : (x,y) : (0,0)
( 0*0 ) + 0 = 0 . Not as per stated equation. So ( x,y ) cant be (0,0)
case 2: (x,y) : (0,1)
(0*1) +0 = 0 Not as per stated equation. So ( x,y ) cant be (0,1)
case 3 : (x,y) : (1,0)
(1*0) + 1=
0 + 1
= 1 = YES so (x,y) can be (1,0)
case 4: (x,y) : (1,1)
(1*1)+ 1
1+1
=1 : YES so (x, y) can be (1,1)
Now we have inconsistent answers for (x,y). We are having (x,y) that can be (1,0) or(1,1).
Insufficient.
Now try with st 1:
trying out all cases ..( I am getting tired to write down all 4 cases)
we will have (x,y) that can be (0,1) or (1,1).
So Insufficient.
Combining both sts 1 & 2:
we can surely say (x,y) should be (1,1)
Becox (1,1) comes out to be one option in both the sts.
Pick C
I think this should come at 700 levels... wat do u say ?
Lets start with st 2 :
(x*y) + x =1
case 1 : (x,y) : (0,0)
( 0*0 ) + 0 = 0 . Not as per stated equation. So ( x,y ) cant be (0,0)
case 2: (x,y) : (0,1)
(0*1) +0 = 0 Not as per stated equation. So ( x,y ) cant be (0,1)
case 3 : (x,y) : (1,0)
(1*0) + 1=
0 + 1
= 1 = YES so (x,y) can be (1,0)
case 4: (x,y) : (1,1)
(1*1)+ 1
1+1
=1 : YES so (x, y) can be (1,1)
Now we have inconsistent answers for (x,y). We are having (x,y) that can be (1,0) or(1,1).
Insufficient.
Now try with st 1:
trying out all cases ..( I am getting tired to write down all 4 cases)
we will have (x,y) that can be (0,1) or (1,1).
So Insufficient.
Combining both sts 1 & 2:
we can surely say (x,y) should be (1,1)
Becox (1,1) comes out to be one option in both the sts.
Pick C
I think this should come at 700 levels... wat do u say ?
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albatross86
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C is the correct choice.
Here's a REALLY detailed explanation for anyone who still has their doubts:
First off, since the operators only work with 0 and 1, we can assume that either x or y can only be 0 or 1.
Let's look at the table.
In order for a + b to be equal to 1, it is necessary that either a or b MUST be 1.
Also, in order for a*b to be equal to 1, both a and b MUST be 1.
Keep that in mind.
Let's look at statement 1:
x*y + y = 1. This tells us that either x*y or y MUST be 1.
What are the possibilities?
If y is 1, then x*y is 0 if x is 0 and 1 if x is 1. Neither value violates the statement.
If y is 0, then x*y is 0, which would make x*y + y = 0, which violates the statement.
So we conclude that y is 1, but x*y could be 0 or 1. INSUFFICIENT.
Let's look at statement 2:
x*y + x = 1. This tells us that either x*y or x MUST be 1.
What are the possibilities?
If x is 1, then x*y is 0 if y is 0 and 1 if y is 1. Neither value violates the statement.
If x is 0, then x*y is 0, which would make x*y + x = 0, which violates the statement.
So we conclude that x is 1, but x*y could be 0 or 1. INSUFFICIENT.
Now let's consider both statements together:
This tells us that x is 1 and y is 1. Therefore, from the table: x*y is also 1. SUFFICIENT
So the answer is C.
Here's a REALLY detailed explanation for anyone who still has their doubts:
First off, since the operators only work with 0 and 1, we can assume that either x or y can only be 0 or 1.
Let's look at the table.
In order for a + b to be equal to 1, it is necessary that either a or b MUST be 1.
Also, in order for a*b to be equal to 1, both a and b MUST be 1.
Keep that in mind.
Let's look at statement 1:
x*y + y = 1. This tells us that either x*y or y MUST be 1.
What are the possibilities?
If y is 1, then x*y is 0 if x is 0 and 1 if x is 1. Neither value violates the statement.
If y is 0, then x*y is 0, which would make x*y + y = 0, which violates the statement.
So we conclude that y is 1, but x*y could be 0 or 1. INSUFFICIENT.
Let's look at statement 2:
x*y + x = 1. This tells us that either x*y or x MUST be 1.
What are the possibilities?
If x is 1, then x*y is 0 if y is 0 and 1 if y is 1. Neither value violates the statement.
If x is 0, then x*y is 0, which would make x*y + x = 0, which violates the statement.
So we conclude that x is 1, but x*y could be 0 or 1. INSUFFICIENT.
Now let's consider both statements together:
This tells us that x is 1 and y is 1. Therefore, from the table: x*y is also 1. SUFFICIENT
So the answer is C.
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liferocks
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For me its C
From 1,
if y=0 ,x*0=0 and (x*0)+0=0...does not satisfy the condition..hence Y=1..but x can be either 1 or 0..not sufficient to calculate x*y
From 2
same reasoning as 1 will show X=1 but no conclusion for Y..hence not sufficient
combining, x and y both are 1..so x*y=1..sufficient
@dkumar.83,can you please confirm that no information is missing in the question?because in the picture first line looks truncated. Also please provide the official explanation as none of us have agreed with OA with the information provided.
From 1,
if y=0 ,x*0=0 and (x*0)+0=0...does not satisfy the condition..hence Y=1..but x can be either 1 or 0..not sufficient to calculate x*y
From 2
same reasoning as 1 will show X=1 but no conclusion for Y..hence not sufficient
combining, x and y both are 1..so x*y=1..sufficient
@dkumar.83,can you please confirm that no information is missing in the question?because in the picture first line looks truncated. Also please provide the official explanation as none of us have agreed with OA with the information provided.
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Lewis Carroll
2 possibilties for each stmt of the 2 statements.
Stmt 1 x*y + y
x ...y......... x*y........x + y.....x*y + y
0 ...1........... 0............1............1
1 ...1........... 1...........1............1
Stmt 2 x*y + x
x ...y......... x*y........x + y.....x*y + y
0...1............ 0.............1........... 1
1... 1........... 1.............1........... 1
In combining the 2 stmts, since each of the stmts has x =1 , y = 1, then that should be the truly shared correct answer.
Stmt 1 x*y + y
x ...y......... x*y........x + y.....x*y + y
0 ...1........... 0............1............1
1 ...1........... 1...........1............1
Stmt 2 x*y + x
x ...y......... x*y........x + y.....x*y + y
0...1............ 0.............1........... 1
1... 1........... 1.............1........... 1
In combining the 2 stmts, since each of the stmts has x =1 , y = 1, then that should be the truly shared correct answer.
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Could anybody please post the question. I really am not understanding the solution...
This seems to be an important question...
This seems to be an important question...
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