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Source: — Data Sufficiency |

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by mikeCoolBoy » Sun Jun 21, 2009 3:07 am
I think the answer should be E

X = sqrt(2) X = 1.4 this fulfill statement 1 and 2 and y = 47/5
X = 2 this fulfill statement 1 and 2 and y = 9

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by SanjeevK » Sun Jun 21, 2009 3:21 am
IMO E

x^2 + 5y = 49
A: 1<x<4. for x = 2, we have y = 9. for x = 2.5, y is not an integer. Hence insufficient
B: x^2 is an integer. if x^2 = 4, y is integer. If x^2 = 3, y is not an integer. Hence insufficient

Combining A and B also doesn't give unique value of y.

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by ketkoag » Tue Jun 23, 2009 12:20 pm
mikeCoolBoy wrote:I think the answer should be E

X = sqrt(2) X = 1.4 this fulfill statement 1 and 2 and y = 47/5
X = 2 this fulfill statement 1 and 2 and y = 9
ohh, how i missed that? what was i thinking... :)
thanks.....

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by hetavdave » Wed Jun 24, 2009 1:23 am
IMO- C.

1) 1<x<4
x can be 2.5,3.5 whose square root is not an integer. hence insufficient

2) x^2 is an integer.
not sufficient. can be 3,4,5

for if 1<x<4 and x^2 is an integer, that leaves with 2 choices for x i.e. 2 and 3

i.e. for x=2
4 + 5y = 49
hence y is an integer

for x =3,
9+5y = 49 is also an integer

please correct me if i am wrong.

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by sanjib » Wed Jun 24, 2009 3:06 am
for Hetavdave.
It is E
because in second option it says x^2 is integer.
So X^ 2 could be 1,2,3,4......
so please square root all of them that would give lot of numbers that would satisfy 1<x<4 and ultimately not necesserely y has to be a integer.
Thanks

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by hetavdave » Wed Jun 24, 2009 3:58 am
sanjib wrote:for Hetavdave.
It is E
because in second option it says x^2 is integer.
So X^ 2 could be 1,2,3,4......
so please square root all of them that would give lot of numbers that would satisfy 1<x<4 and ultimately not necesserely y has to be a integer.
Thanks
Sorry guys i am still not getting this :(

I agree with sanjib's point above that x^2 can mean 1,2,3,4 but i am not able to find that fractional number that is between 1 and 4 and whose square is an integer.

hence i went for C

can you please elaborate with an example.

thanks

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by david4431 » Wed Jun 24, 2009 4:41 am
Answer: E.

S1 tells you that 1<x<4. Since x does not necessarily have to be an integer, this is insufficient. x could be 2.5 for example.

S2 tells you that x^2 is an integer. x could be 8, which would make y a non-intger.

Statements combined. hetavdave, here is an explanation for you: suppose x^2 = 8. This means that x would equal 2.8284... and would satisfy both statements. x^2 would be an integer and x would be between 1 and 4. In this case, y is not an integer. In a different case, if x was equal to 3, y would be an integer.

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by hetavdave » Wed Jun 24, 2009 7:24 am
david4431 wrote:Answer: E.

S1 tells you that 1<x<4. Since x does not necessarily have to be an integer, this is insufficient. x could be 2.5 for example.

S2 tells you that x^2 is an integer. x could be 8, which would make y a non-intger.

Statements combined. hetavdave, here is an explanation for you: suppose x^2 = 8. This means that x would equal 2.8284... and would satisfy both statements. x^2 would be an integer and x would be between 1 and 4. In this case, y is not an integer. In a different case, if x was equal to 3, y would be an integer.
yes...dunno why, i was not coming out of the fractions.thanks all :)