Joules, or the unit of work, is derived from the equation of Newton multiplied to distance. That is, the force applied to an object is multiplied to the distance it travelled when the force is applied to it. Thus, the formula of Joules would be Newton x distance. taken into their units, it would look like as J = N x d. Now in this problem, the missing variable would be distance since it is the distance that was asked. The given variables would be the force and the work done. What happens would be that the work done is divided by the force exerted to get the distance. So, 500 Newtons would be divided to 250 Joules. It would look like this
250 J / 500 N = ?m
the answer would be 0.5m
0.5m would be the distance that pertains as to how high she jumped.