A voltage supply varying between 8 V and 12 V is in series with a 5-ohm resistor and a parallel combination of a zener diode (Rz = 0) and a load resistor. The diode has a zener voltage of 5 V and can regulate the load voltage when the series current (through the 5-ohm resistor) is between 50 mA and 1 A. Find the range of the load current for regulation.

Below is a quick diagram of the circuit from falstad. Note the values don't match (particularly, load resistance is not given).

From my understanding, the lowest series current in this set up is [ V(ss, min) - V(z) ] / R(s) = [ 8 - 5 ] / 5 = 0.6 A, which is a lot higher than the 50-mA lower end for regulation provided by the problem. On the other end, [ V(ss, max) - V(z) ] / R(s) = [ 12 - 5 ] / 5 = 1.4 A, which exceeds the upper limit for regulation, 1 A. So I'm not entirely sure what's going on; am I supposed to just ignore the values for V(ss) > 10 V and only consider 8 V < V(ss) < 10 V for regulation?

I also do not know how to find the load current. I know V(load) = V(z) = 5 V in regulation, but the load resistance is left unspecified. The only other way I can think of to find load current is to subtract the diode current from the series current, but I can't figure out a way to figure out the diode current separately.

Any help is appreciated.