Let "h" be the height the box lifted (the unknown quantity under the problem's question).


The mass of the box is   = 10 kilograms  (here 10 in the denominator represents the gravity acceleration of 10 m/s^2).


The work done by the force  F = 500 N  is  A = F*h = 500*h  joules.


Its part of 2000 J was spent to change the kinetic energy (KE).


The rest of the job, 500h - 2000 was spent to change the potential energy mgh.


So, we write this equation

    500h - 2000 = 10*10*h,

or

    500h - 2000 = 100h

    500h - 100h = 2000

       400h     = 2000

           h     =  = 5 meters.


ANSWER.  The box was lifted 5 meters up.