mvictor wrote:
I understand why A is wrong...for ex. x=0.5...
I understand why B is wrong
but can't see why C is ok...hm..
Hi,
1) Statement 1 gives you 2x-1 is odd ..
so 2x is even ..
x can be
i) odd,
ii) even or
iii) a fraction with a denominator of 2 in its simplified form..
2) statement 2 gives you x^3 is odd..
this gives you two cases of x..
i) x is odd, or
ii) x is third root of some odd number..
You have correctly realized that A and B are not sufficient alone..
But combined..
for both 1 and 2 to be true, the value of x has to be something that fits in both the cases..look at the possible values of x, only
X IS ODD is common to both..
so x is odd and C is the answer..
Hope it helps you
Sorry, but I think that a fraction with a denominator of 2 in its simplified form is not an option, because then 2x would be odd, and 2x -1= even.
The only thing that statement 1 gives us is that x is an integer.
Clipper Ledgard
GMAT Coach