The central equation of quantum is the Schrodinger Equation. The solutions of that equation are called wave functions and they describe the state of a particle. A particle can be in a bound state, or a scattering state. In a bound state, the potential energy at some barrier is greater than the energy of the particle, while a scattering state is where the energy of the particle is greater than the potential energy at the barrier. (This is a horribly simplified view, but oh well.)
In the case of a number of potentials it's easy to determine if the particle will be in a bound or scattering state. If the energy of a particle is smaller than the value of the potential energy at infinity, and -inifinity then the particle is in a bound state. Otherwise, it's in a scattering state. (Again, this is simplified).
In this problem, you get to tell if a particle is in a bound state or a scattering state.