Maximize Linear Programming using linprog - returns absurd results

I have to maximize the function given below: f(x,y, z) = 10x + 8y + 5z; subject to

x + 2y + 2z <=1600;

3x + 2y + z <= 600;

x>=0;

y>=0;

z>=0;

I tried to find out the value using linprog() function:

f = [-10 -8 -5]
A = [1 2 2; 3 2 1]
b = [1600 600]
linprog(f, A, b)

But i am getting some absurd values:

X =
   1.0e+03 *

   -0.5000
    1.0500
         0

val =
  -3.4000e+03

Where did i go wrong? Any help would be really appreciated.

[Torsten]

You forgot to include 0 as lower bound for x,y and z.