harrish.icemansilverarrows Wrote:On the number line the distance bet x & y is greater than the distance between x & z.
given this statement, the number line can appear in one of exactly four ways:
case 1:--------------------x------z-------y---------
case 2: -------------z------x--------------y---------
case 3: -----y--------------x------z-----------------
case 4: -----y------z-------x------------------------
cases 1 and 4 are "yes" to the question; cases 2 and 3 are "no". since
the GOAL is to TRY FOR "INSUFFICIENT" (as in just about any non-algebraic DS problem), you should try to get one instance of case 1 or 4, and one instance of case 2 or 3.
a) xyz<0
you can make any of the four cases with 3 negative numbers, so this statement is insufficient (you don't even have to consider the cases in which some of them are positive).
e.g.
x = -3, z = -2, y = -1 --> case 1 ("yes" to the question)
z = -4, x = -3, y = -1 --> case 2 ("no" to the question)
b) xy<0
again, easy to get any of the three cases -- x and y just have to be one positive and one negative, and z can be, well, anything at all.
e.g.
x = -2, z = 1, y = 2 --> case 1 ("yes" to the question)
z = -3, x = -2, y = 2 --> case 2 ("no" to the question)
together:
if you have both statements, then you know:
x and y are one positive, one negative;
z is positive.
you can still get both answers:
x = -2, z = 1, y = 2 --> case 1 ("yes" to the question)
y = -2, x = 2, z = 3 --> case 2 ("no" to the question)
still insufficient.
answer = (e)