Is a product of three integers XYZ a prime? (1) X=Y (2) Z=1

Question

Is a product of three integers XYZ a prime?

(1) X=–Y
(2) Z=1

MBA04 · Answer

C?

From 1, maybe or maybe not
From 2, nothing

Together, you now it is impossible to get a prime

tzolkin · Answer

Ans : C

1) Z could be -ve thus => insuff
2) X*Y could be prime => insuff

Combined : 

X*Y*Z = -ve number 

and since X=-Y, X*X can never be prime

Ans NO => Suff

stolyar · Answer

You move in the right direction, either set is not sufficient. Combine -- the product is –X^2, a negative number can NEVER be a prime! If X=0, then tha product is 0, which is not prime either. Thus, C.

FN · Answer

I would say this has to be B...

x*y*z=prime?

1) x=-y, lets see if x=2, then y=-2 x*y=-4*if z=-1 then product not a prime..suppose x=-1 y=1 then -1*z if z=-3 then product is 3 (prime) Insuff

2) z=1, taking above example.....

1*-2*2=-4 not a prime..you can try other numbers...it will always never be a prime..B has to be it...

I wish styolar was around..to verify.but i think B is the right

terp26 · Answer

B is insuff 

because 1 * 1 * 1 Not Prime
 2 * 1 * 1 Prime

Is a product of three integers XYZ a prime? (1) X=Y (2) Z=1

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