Lesson: Even and Odd Integers

Comment on Even and Odd Integers

What the answer to the Greenlight Test Prep question? I get iii as an answer, but not i or ii, so I did something wrong...
greenlight-admin's picture

Question link: https://gre.myprepclub.com/forum/m-and-n-are-positive-integers-if-mn-2m-...

Oops I forgot to include the correct answer.

Thanks for the heads up! It's fixed now.

Cheers,
Brent

Hi Brent,
I solved the question as follows https://gre.myprepclub.com/forum/if-m-19-is-an-even-integer-which-of-the-following-must-tru-1846.html

Property Even/Odd is an integer and even. This means that its final value is even. As for positive or negative , it may or may not be so we cant be sure.
greenlight-admin's picture

Question link: https://gre.myprepclub.com/forum/if-m-19-is-an-even-integer-which-of-the...

Looks good to me!!

Cheers,
Brent

https://gre.myprepclub.com/forum/qotd-26-x-y-and-z-are-consecutive-even-integers-2746.html

Is there any specific ordering of x,y,z that we have to follow for this question? I think we can assume values for the variables in any order necessary for reaching a conclusion. Please correct me if I am wrong.
greenlight-admin's picture

Question link: https://gre.myprepclub.com/forum/qotd-26-x-y-and-z-are-consecutive-even-...

Good question. Since there's no text suggesting the ordering of the integers, x, y and z can be arranged in any order.

Cheers,
Brent

https://gre.myprepclub.com/forum/if-x-y-and-z-are-consecutive-positive-integers-with-x-y-13966.html
For this question, I thought that if the sum is even that the numbers all have to be even. The rule that odd+-even=odd, so this rule dosent work for this problem.
greenlight-admin's picture

Question link: https://gre.myprepclub.com/forum/if-x-y-and-z-are-consecutive-positive-i...

The rules for addition and subtraction are as follows:
#1. ODD +/- ODD = EVEN
#2. ODD +/- EVEN = ODD
#3. EVEN +/- EVEN = EVEN

Notice that these rules apply to adding or subtracting TWO values (not three).

Also notice that ODD + ODD = EVEN, and EVEN + EVEN = EVEN
So, if we know the sum up two numbers is EVEN, those two numbers can both the odd, or they can both be even.

Does that help?

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