Is the product of X and Y a prime? 1. X^2=1 2. Y is a

Question

Is the product of X and Y a prime?

1. X^2=1
2. Y is a positive and prime, X is positive but not prime

netcaesar · Answer

How did you get C? What is your approach?

GMATBLACKBELT · Answer

1: x=1 or -1. Nothing on Y. Insuff

2: Y is prime so can be 2,3,5,7, etc... X is + but not prime. X can be 1,4,6, etc...

Together X must be 1 and Y is a prime.

Thus XY is prime

pmenon · Answer

i get C as well

stat 1 says that x= +1 or -1, but nothing about y. insuff.

stat 2 says that y=2,3,5,7... and x=1,4,6,8. some of the products are prime, and some are not. insuff.

together, we know that y=2,3,5,7... and x=+1 or -1. in either case, xy is a prime. suff.

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