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An even and an odd integer are multiplied together. Which of the follo [#permalink]
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17 Apr 2015, 04:48
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82% (00:39) correct 18% (00:32) wrong based on 113 sessions
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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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17 Apr 2015, 05:03
Bunuel wrote: An even and an odd integer are multiplied together. Which of the following could not be the square of their product?
(A) 36 (B) 100 (C) 144 (D) 225 (E) 400
Kudos for a correct solution. 36=\(6^2\)=2*3>Possible 100=\(10^2\)=2*5>Possible 144=\(12^2\)=4*3>Possible 225=\(15^2\)=3*5>Not Possible 400=\(20^2\)=4*5>Possible Answer: D



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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18 Apr 2015, 11:19
Hi All, This is an example of a question that can be solved with Number Properties; NPs show up in a variety of questions on Test Day (including many DS questions), so putting some extra practice into this category is a good idea for most Test Takers. Here, we're told to take the product of an EVEN integer and an ODD integer. (Even)(Odd) = Even. Next, we're asked to SQUARE that result. (Even)^2 = Even. The question asks for the answer that could NOT be the result of using these Number Properties as described. Since we know the end result MUST be Even, there's only one answer here that could NOT occur.... Final Answer: GMAT assassins aren't born, they're made, Rich
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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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18 Apr 2015, 14:32
Product of an even and odd integer will at least be divisible by 2
So , if we square the product, then it will be at least divisible by 4
only 225, among the given list of nos is not divisible by 4 and hence is the reqd answer
Should be D



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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19 Apr 2015, 00:20
\(even\,*\,odd\,=\,even\) \(even^2\,*\,odd^2\,=\,even*(even\,*odd\,*odd)\)\(\,=\,even\); resultant should be even here \(225\) is the odd one out
Answer D



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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19 Apr 2015, 03:22
[quote="Bunuel"]An even and an odd integer are multiplied together. Which of the following could not be the square of their product?
(A) 36 (B) 100 (C) 144 (D) 225 (E) 400
2*3=6 and 6^2=36 5*2=10 and 10^2=100 3*4=12 and 12^2=144 5*4=20 and 20^2=400
Answer D



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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19 Apr 2015, 21:30
Hi Bunuel, I think there might be a mistake here, the GMAT timer is showing C as the correct answer, is the answer not D?



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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20 Apr 2015, 05:08
Bunuel wrote: An even and an odd integer are multiplied together. Which of the following could not be the square of their product?
(A) 36 (B) 100 (C) 144 (D) 225 (E) 400
Kudos for a correct solution. VERITAS PREP OFFICIAL SOLUTIONOne way to approach this problem is to start with an even and an odd integer and plug them in to the parameters set by the problem. If we begin with two and three, we see that the product is six and the square of the product is thirty six. (2)(3) = 6; 6^2 = 36 Similarly we can see that two and five, three and four, and four and five all give us possible answer choices. (2)(5) = 10; 10^2 = 100 (4)(3) = 12; 12^2 = 144 (4)(5) = 20; 20^2 = 400 Answer choice (D) is also a perfect square, but if we take the square root of it, we see that the result is fifteen, which is not divisible by an even and an odd number. Thus the only answer that could not be the squared product of an even and odd integer is answer choice (D).
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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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20 Apr 2015, 05:09



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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21 Apr 2015, 02:17
Bunuel wrote: An even and an odd integer are multiplied together. Which of the following could not be the square of their product?
(A) 36 (B) 100 (C) 144 (D) 225 (E) 400
Kudos for a correct solution. (A) 36 (1×6)^2 (B) 100 (1×10)^2 (C) 144 (1×12)^2 (D) 225(all factors are odd for this number , so this is our answer) (E) 400(1×20)^2
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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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26 Apr 2015, 22:07
Bunuel wrote: achilds wrote: Hi Bunuel, I think there might be a mistake here, the GMAT timer is showing C as the correct answer, is the answer not D? Yes, the correct answer is D. Edited the OA in the original post. Thank you for noticing this. This can be simply be done in a sec, even * odd always gives even, and even square is even, except 225 rest all are even



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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15 May 2017, 19:39
even times odd should give us even result.
The only add answer choice, 225, 15 times 15 is odd and it couldn't be the multiplication of and odd and an even number.



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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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15 May 2017, 21:35
Bunuel wrote: An even and an odd integer are multiplied together. Which of the following could not be the square of their product?
(A) 36 (B) 100 (C) 144 (D) 225 (E) 400
Kudos for a correct solution. (even*odd)^2 = ? Checking options (A) 36 = 2^2*3^2 possible (B) 100 = 2^2*5^2 Possible (C) 144 = 2^4*3^2 Possible (D) 225 = 3^2*5^2 NOT Possible as no even power of 2 is available (E) 400 Answer: Option D
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Re: An even and an odd integer are multiplied together. Which of the follo [#permalink]
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15 May 2017, 22:18
Bunuel wrote: An even and an odd integer are multiplied together. Which of the following could not be the square of their product?
(A) 36 (B) 100 (C) 144 (D) 225 (E) 400
Kudos for a correct solution. Did not take much time, simply scanned the values as Even or Odd and there it was D. Plugging numbers is a good way to cross check and still worth doing it considering scanning of numbers did not take much time.
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Re: An even and an odd integer are multiplied together. Which of the follo
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