GMAThirst wrote:
if w + Z = 28, what is the value of wz
1. w and z are positive integers
2. w and z are consecutive odd integers
Hi GMAThirst, let's examine these statements one at a time:
1. w and z are positive integers.
We know that both must be positive, so this eliminates 30 and -2, but it could be 1 and 27, 2 and 26, 3 and 25, etc. All of which have different products (1x27=27, 2x26=52, etc) A is insufficient on its own
2. w and z are consecutive odd integers
This would have to be 13 and 15. No other positive consecutive odd integers would add up to 28. Statement A makes us wonder about negative numbers, what about -13 and -15? Well they would add up to -28, which isn't the same as +28, so they're out as possibilities. What about other negative consecutive odd integers? Nothing is ever going to give you anything other than a negative number, so no negative numbers could work here. Statement 2 is thus sufficient on its own, with no need to bring in statement #1. (w*z must be either 13*15 or 15*13, either way giving the answer of 195 by commutativity)
Answer: B.
Hope this helps!
-Ron
_________________