Math Help - a real number proof question..

1. a real number proof question..

i got a real number called "x"

prove that if it follows this rule n>x>=0

for every real and positive "n"

then "x" must have the value x=0

??

i dont know how to solve it because
from this expression
n>x>=0

"x" must not be equaled to 0

i cant see the way to solve it

??