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If x and y are consecutive odd integers such that x < y, what is the value of y + x?

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by BTGModeratorVI » Wed Oct 07, 2020 7:14 am

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If x and y are consecutive odd integers such that x < y, what is the value of y + x?

(1) The product of xy is negative.
(2) The sum x + y is the square of an integer

Answer: A
Source: Magoosh
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Source: — Data Sufficiency |

BTGModeratorVI wrote:
Wed Oct 07, 2020 7:14 am
If x and y are consecutive odd integers such that x < y, what is the value of y + x?

(1) The product of xy is negative.
(2) The sum x + y is the square of an integer

Answer: A
Source: Magoosh
Target question: What is the value of y + x?

Given: x and y are consecutive odd integers such that x < y

Statement 1: The product of xy is negative
In order for the product xy to be NEGATIVE, it must be the case that one value is POSITIVE and one value of NEGATIVE.
Since x and y are CONSECUTIVE ODD integers, it must be the case that x = -1 and y = 1
This is the ONLY way to satisfy statement 1.
If x = -1 and y = 1, then x + y = (-1) + 1 = 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: The sum x + y is the square of an integer.
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = 1 and y = 3. Notice that x + y = 1 + 3 = 4, and 4 IS the square of an integer (4 = 2²) In this case, the answer to the target question is x + y = 4
Case b: x = 7 and y = 9. Notice that x + y = 7 + 9 = 16, and 16 IS the square of an integer (16 = 4²) In this case, the answer to the target question is x + y = 16
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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