consecutive integers?

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consecutive integers?

by rahul.s » Sat Jan 30, 2010 9:29 am
are integers x, y and z consecutive?

1) y equals the arithmetic mean of x and z
2) x = -z

[spoiler]OA's E, but I opted for A[/spoiler] :?

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by thephoenix » Sat Jan 30, 2010 9:36 am
S1) 2,4,6 Y IS MEAN BUT X,Y,Z ARE NOT CONSECUTIVE
1,2,3 Y IS MEAN AND X,Y,Z ARE CONSECUTIVE
INSUFF
S2) INSUFF

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by sars72 » Sat Jan 30, 2010 9:49 am
Rahul, i think the mistake you may be making is that you are consider something like 1,3,5 to be consecutive integers when they are not... silly mistake, which I have made on occassion. If not, then here is the explanation to help you out:
are integers x, y and z consecutive?
1) y equals the arithmetic mean of x and z
2,4,6 -> 4=(2+6)/2 --> not consecutive

1,2,3 -> 2(1+3)/2 --> consecutive

Therefore, since we both yes & no, the statement by itself is insufficient -> Choices A & D are eliminated
2) x = -z
we have nothing about y, so by itself the statement is insufficient -> B is eliminated

combining 1 & 2 ->
-1,0,1 -> 0= (-1+1)/2 && -1 = -(1) -->consecutive
-2,0,2 -> 0= (-2+2)/2 && -2=(-2) --> not consecutive
Therefore the two statements combined are also insufficient, and thus E is the correct answer.

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by rahul.s » Sat Jan 30, 2010 10:29 am
again, my bad.

just not my day.

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by sars72 » Sat Jan 30, 2010 10:48 am
rahul.s wrote:again, my bad.

just not my day.
cheer up mate. Better you make mistakes now than on test day, eh? :D

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by rahul.s » Sat Jan 30, 2010 8:21 pm
sars72 wrote:
rahul.s wrote:again, my bad.

just not my day.
cheer up mate. Better you make mistakes now than on test day, eh? :D
haha. true.