Hi,
1. x/y = 3 means x = 3y, you may see that x can not be equal to y while x = 3y. However, watch out!
If both x and y are Zero, then x = y = 3y
Insuf.
2. Same as 1. As x = 3y means x/y = 3
Insuf.
1&2. As 2 is the same to 1, 2 does not provide any additional information. Then 1 & 2 : insuf.
My answer E. Both 1 & 2 together are insuf.
DS question
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Source: Beat The GMAT — Data Sufficiency |
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sumit.sinha
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Brilliantlimestone wrote:Hi,
1. x/y = 3 means x = 3y, you may see that x can not be equal to y while x = 3y. However, watch out!
If both x and y are Zero, then x = y = 3y
Insuf.
2. Same as 1. As x = 3y means x/y = 3
Insuf.
1&2. As 2 is the same to 1, 2 does not provide any additional information. Then 1 & 2 : insuf.
My answer E. Both 1 & 2 together are insuf.
Pick E
Cheers,
Sumit
Sumit
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pradeepkaushal9518
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kvcpk
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IMO A.frank1 wrote:Is x = y ?
(1) x/y = 3
(2) x = 3y
Source:Nova Data Prep
OA later
(1) x/y = 3
x = 3y.
x=y only when x=y=0. But y cannot be 0. because it is in denominator.
Hence x can never equal y.
SUFF
(2) x = 3y
x =y=0 will suffice in this case. we dont have y in denominator.
x=3,y=1 will aslo satisfy.
hence INSUFF
pick A.
Hope this helps!!
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frank1
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Thanks for your suggestionselango wrote:Yes this is not a good question.
Frank always use authentic materials.
I normally donot use Nova's materials but
I think Nova is not bad publication when it comes to GMAT.
At least in this case.I consider this because this question is from DS book(The whole book is on DS....which i have not found with other publications..) and most questions seems like they are as per gmat standards.
This question is bit tricky.....even i dont agree with OA....thats why i have posted it here for comments....
I agree it is not good question......but i think it is not that bad either(out of gmat scope)
OA is A...
Now my question is CANNOT BE that statement 2 converted to Statement 1 using cross multipication ....that is where i am confused...x/y equals 3 indicates the following two points:
1) x is not equal to 0, because then x/y would
equal 0, not 3
and
2) y is not equal to 0, because then x/y would
be an undefined infinite value and not 0.
Hence, x - y ≠0 or x ≠y. The statement is
sufficient.
GMAT score is equally counted as your GPA and 78 clicks can change you life.
I and II are the same statement (cross multiplication as you mentioned) so the answer can only be D or E; the OA is incorrect.
frank1 wrote:Thanks for your suggestionselango wrote:Yes this is not a good question.
Frank always use authentic materials.
I normally donot use Nova's materials but
I think Nova is not bad publication when it comes to GMAT.
At least in this case.I consider this because this question is from DS book(The whole book is on DS....which i have not found with other publications..) and most questions seems like they are as per gmat standards.
This question is bit tricky.....even i dont agree with OA....thats why i have posted it here for comments....
I agree it is not good question......but i think it is not that bad either(out of gmat scope)
OA is A...Now my question is CANNOT BE that statement 2 converted to Statement 1 using cross multipication ....that is where i am confused...x/y equals 3 indicates the following two points:
1) x is not equal to 0, because then x/y would
equal 0, not 3
and
2) y is not equal to 0, because then x/y would
be an undefined infinite value and not 0.
Hence, x - y ≠0 or x ≠y. The statement is
sufficient.
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goyalsau
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Answer should be D.Viktri wrote:I and II are the same statement (cross multiplication as you mentioned) so the answer can only be D or E; the OA is incorrect.
Saurabh Goyal
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frank1
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I also agree with you.
Here is the official explanation from Nova DS prepation Book
Here is the official explanation from Nova DS prepation Book
Is x = y ?
(1) x/y = 3
(2) x = 3y
Statement (1): x/y = 3
x/y equals 3 indicates the following two points:
1) x is not equal to 0, because then x/y would
equal 0, not 3
and
2) y is not equal to 0, because then x/y would
be an undefined infinite value and not 0.
So, cross-multiplying the equation (valid because
we know the denominator y ≠0) yields x = 3y.
Subtracting y from both sides yields x - y = 2y.
Since y is not equal to 0, 2y is not equal to zero.
Hence, x - y ≠0 or x ≠y. The statement is
sufficient.
Statement (2): x = 3y
If x = y = 0, x = 3y and still x = y is true.
But if x ≠0, since x = 3y, x would not equal y just
as in Statement (1).
We have a double case, and therefore the statement
is not sufficient.
The answer is (A).
GMAT score is equally counted as your GPA and 78 clicks can change you life.
