Hi Experts,
For integers x and y, is x+y even?
(1) x^2−y^2 is even
(2) x−y is even
I feel the answer should be E but the answer given is D
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Statement 1: x² - y² is even[email protected] wrote:Hi Experts,
For integers x and y, is x+y even?
(1) x^2−y^2 is even
(2) x−y is even
I feel the answer should be E but the answer given is D
Case 1: x² - y² = even - even.
Here, x and y must both be even.
In this case, x+y = even + even = even.
Case 2: x² - y² = odd - odd.
Here, x and y must both be odd.
In this case, x+y = odd + odd = even.
Since x+y is even in both cases, SUFFICIENT.
Statement 2: x-y is even
Case 1: x-y = even - even
In this case, x+y = even + even = even.
Case 2: x-y = odd - odd
In this case, x+y = odd + odd = even.
Since x+y is even in both cases, SUFFICIENT.
The correct answer is D.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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