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Is the positive integer p even?

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Is the positive integer p even?

by missrochelle » Sat Aug 14, 2010 7:45 am
Is the positive integer p even?

(1) p^2 + p is even.

(2) 4p + 2 is even.

ANSWER: E


My question - why can't you use addition properities of odd and even without multiplying?
For example, if p^2 + p is even.... then p must be even since only an even number squared is even. And even + even = even.
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by Gurpinder » Sat Aug 14, 2010 7:49 am
missrochelle wrote:Is the positive integer p even?

(1) p^2 + p is even.

(2) 4p + 2 is even.

ANSWER: E


My question - why can't you use addition properities of odd and even without multiplying?
For example, if p^2 + p is even.... then p must be even since only an even number squared is even. And even + even = even.
yea....but it works the other way too....

if p = 1 lets say, then 1^2 = 1 and 1+1 = 2.

for DS questions, when ever the answer is uncertain, its not sufficient.
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by kvcpk » Sat Aug 14, 2010 7:52 am
missrochelle wrote:Is the positive integer p even?

(1) p^2 + p is even.

(2) 4p + 2 is even.

ANSWER: E


My question - why can't you use addition properities of odd and even without multiplying?
For example, if p^2 + p is even.... then p must be even since only an even number squared is even. And even + even = even.
odd+odd is also even.

odd^2 is odd.

I think you missed this.

Hope this helps!!
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don't be afraid of failure and don't abandon it.
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by missrochelle » Sat Aug 14, 2010 7:53 am
I did miss that..... Not sure how! but thanks for pointing it out.
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