Question

For ps2a.py, how can the combination be generated, and how do we know what is "feasible"?

Answer 1

Feasible aka possible. You will need to find a way to create combinations. hint: loops will be very handy here.

Answer 2

to know what is 'feasible' ... read the readings for the first three lectures. also the tutorial in the Python docs is pretty good - it should be on your computer as well as here:
http://docs.python.org/tutorial/