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If x and y are two different prime numbers, which of the [#permalink]
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08 Jun 2012, 09:14
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If x and y are two different prime numbers, which of the following cannot be true? A. xy is odd. B. x + y is even. C. x + y is odd. D. xy is even. E. x/y is an integer
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Last edited by Bunuel on 14 Jul 2012, 04:08, edited 1 time in total.
Edited the question and added the OA.



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Re: If x and y are two different prime numbers, which of the [#permalink]
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08 Jun 2012, 09:29



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Re: If x and y are two different prime numbers, which of the [#permalink]
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13 Jul 2012, 09:43
solved in 00:22
Ans : E
followed this strategy
Odd*odd = odd even*odd=even odd+odd=even even+even=even



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If x and y are two distinct prime numbers, which of the following cann [#permalink]
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09 Sep 2014, 18:24
If x and y are two distinct prime numbers, which of the following cannot be true? A. xy is odd. B. xy is even. C. x  y is odd. D. x  y is even. E. \(\frac{x^2}{y}\) is an integer
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Last edited by PareshGmat on 09 Sep 2014, 21:37, edited 2 times in total.



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Re: If x and y are two distinct prime numbers, which of the following cann [#permalink]
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09 Sep 2014, 19:28
Hi PareshGmat,
The best way to attack this question is to PlugIn simple prime numbers to prove the answer choices. Don't forget that 2 is the first prime number, and also the only even one. As a refresher, the definition of a prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
(A) x*y is odd. Let's choose x=3, y=5, so x*y = 15.
(B) x*y is even. Let's choose x=2, y=3, so x*y = 10.
(C) xy is odd. Let's choose x=3, y=2, so xy = 1.
(D) xy is even. Let's choose x=5, y=3, so xy = 2.
Thus, E is the only answer choice left, and must be the answer.
Hope this helps! Good luck studying!
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Re: If x and y are two distinct prime numbers, which of the following cann [#permalink]
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09 Sep 2014, 21:05
PareshGmat wrote: If x and y are two distinct prime numbers, which of the following cannot be true?
A. xy is odd. B. xy is even. C. x  y is odd. D. x  y is even. E. \(\frac{x^2}{y}\) is an integer Whenever you come across prime numbers and the terms odd and even in a question, you must think of 2  the only even prime number. All other prime numbers are odd. A. xy is odd. If both x and y are odd, xy can be odd. B. xy is even. If one of x and y is 2 and the other is some other odd prime number, xy will be even. C. x  y is odd. If x is odd and y is 2, xy will be odd. D. x  y is even. If both x and y are odd, xy will be even. So all these are possible. Then answer must be (E). Logically, if x is prime and y is a different prime number, x^2 cannot be divisible by y.
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If x and y are two distinct prime numbers, which of the following cann [#permalink]
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09 Sep 2014, 21:37
PareshGmat wrote: If x and y are two distinct prime numbers, which of the following cannot be true?
A. xy is odd. B. xy is even. C. x  y is odd. D. x  y is even. E. \(\frac{x^2}{y}\) is an integer After reading this problem, things came to my mind are prime numbers, even numbers & odd numbers. However the last option E clicked over. Dividing a prime number with another would never yield an integer. Had it been, the number would had been excluded from prime numbers, isn't it? So selected option = E Believe me, did not do any calculation, number plugging......
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Re: If x and y are two different prime numbers, which of the [#permalink]
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Re: If x and y are two different prime numbers, which of the [#permalink]
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26 Mar 2017, 00:46
If x and y are two different prime numbers, which of the following cannot be true?
A. xy is odd. true, odd*odd is odd and all prime numbers except 2 are odd B. x + y is even. odd+odd =even C. x + y is odd. odd+ odd= even but 2 is also a prime so this can be true D. xy is even. 2*odd = even E. x/y is an integer correct this cannot be true bcause no prime number can be divided by number other than 1 and itself.




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