yezz wrote:

Is a product of three integers XYZ a prime?

(1) X=-Y

(2) Z=1

C for me For XYZ to be prime we need to have a positive product so values could be:

1)1*1*(any prime)

2)1*(-1)*-(any prime)

3) -1*-1*any prime

St 1 tells us that either X or Y is +ve, so we know that XY is -ve. We know nothing about Z. Please note that negative numbers cannot be primes, but there is still a possibility for the variant 2.

St 2 tells us Z=1. we know nothing about X and Y

Combining two statements together we can answer the question:

If X is any number we get a negative product of XYZ, and we know that no prime number can be negative. So answer is NO, thus SUFF