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*triangle* denotes one of the four arithmetic operations

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by abhi332 » Wed Feb 24, 2010 12:23 pm
If *triangle* denotes one of the four arithmetic operations addition, subtraction, multiplication and division, what is the value of 1 *triangle* 2 ?

(1) n *triangle* 0 = n for all integers n.
(2) n *triangle* n = 0 for all integers n.

[spoiler]OA: B[/spoiler]
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Source: — Data Sufficiency |

by firdaus117 » Wed Feb 24, 2010 12:45 pm
(1) n *triangle* 0 = n for all integers n.
Now, n+0=n Accepted
n-0=n Accepted
n*0=0 Rejected
n/0=Indeterminable Rejected
Hence,*triangle* can be + or -.Insuff.
(2) n *triangle* n = 0 for all integers n.
n+n=2n Rejected
n-n=0 Accepted
n*n=n^2 Rejected
n/n=1 Rejected
Hence,*triangle* is - only.Suff.
Option B
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by vineetbatra » Wed Feb 24, 2010 4:34 pm
I agree B.
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by jeffedwards » Wed Feb 24, 2010 5:23 pm
Just pick numbers and see which signs would make the statements true. It's the easiest way for me to see what is going on.

1-could be addition or subtraction - for all integers, n
2-could only be subtraction - for all integers, n

So pick B
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