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Tricky Data Sufficiency

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by swtj912 » Sun Jun 03, 2012 7:55 am
Came across this Data Sufficiency problem, not sure if anyone can help w/ explaining the answer. THANKS!!

What is the value of (x - y)^4?
(1) The product of x and y is 7.
(2) x and y are integers.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
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Source: — Data Sufficiency |

by aneesh.kg » Sun Jun 03, 2012 9:47 am
swtj912 wrote:Came across this Data Sufficiency problem, not sure if anyone can help w/ explaining the answer. THANKS!!

What is the value of (x - y)^4?
(1) The product of x and y is 7.
(2) x and y are integers.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Hi swtj912,

Statement(1):
xy = 7
x and y can hold infinite number of values. No way to find (x - y)^4
INSUFFICIENT

Statement(2):
x and y can have many integral values
For x = 7, y = 1, (x - y)^4 = (6)^4
For x = -7, y = -1, (-7 - (-1)) = (-6)^4 = (6)^4

SUFFICIENT

[spoiler](C)[/spoiler] is the answer.

What's the source?
Aneesh Bangia
GMAT Math Coach
[email protected]

GMATPad:
Facebook Page: https://www.facebook.com/GMATPad
Join the discussion

by vickythakre » Mon Jun 04, 2012 4:59 pm
aneesh.kg wrote:
swtj912 wrote:Came across this Data Sufficiency problem, not sure if anyone can help w/ explaining the answer. THANKS!!

What is the value of (x - y)^4?
(1) The product of x and y is 7.
(2) x and y are integers.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Hi swtj912,

Statement(1):
xy = 7
x and y can hold infinite number of values. No way to find (x - y)^4
INSUFFICIENT

Statement(2):
x and y can have many integral values
For x = 7, y = 1, (x - y)^4 = (6)^4
For x = -7, y = -1, (-7 - (-1)) = (-6)^4 = (6)^4

SUFFICIENT

[spoiler](C)[/spoiler] is the answer.

What's the source?
Hi Aneesh,

Isn't it true that we have to B is in isolation and which can be anything in integer. So B is also insufficient.
Although combining both of them we get the same answer as + or - 6 ^4.

Please correct me if i am missing something.
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by aneesh.kg » Mon Jun 04, 2012 8:40 pm
vickythakre wrote:
aneesh.kg wrote:
swtj912 wrote:Came across this Data Sufficiency problem, not sure if anyone can help w/ explaining the answer. THANKS!!

What is the value of (x - y)^4?
(1) The product of x and y is 7.
(2) x and y are integers.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Hi swtj912,

Statement(1):
xy = 7
x and y can hold infinite number of values. No way to find (x - y)^4
INSUFFICIENT

Statement(2):
x and y can have many integral values
For x = 7, y = 1, (x - y)^4 = (6)^4
For x = -7, y = -1, (-7 - (-1)) = (-6)^4 = (6)^4

SUFFICIENT

[spoiler](C)[/spoiler] is the answer.

What's the source?
Hi Aneesh,

Isn't it true that we have to B is in isolation and which can be anything in integer. So B is also insufficient.
Although combining both of them we get the same answer as + or - 6 ^4.

Please correct me if i am missing something.
Hi,

Yes, I missed typing a 'INSUFFICIENT' after Statement(2).
Only combining them gives us an answer.
Aneesh Bangia
GMAT Math Coach
[email protected]

GMATPad:
Facebook Page: https://www.facebook.com/GMATPad
Join the discussion