Thanks for the hints.
For m=1, then initially we have prob of p having it loaded, before the first round we have two case
loaded: prob of p
not loaded: 1-p
after 1st round
not loaded: 1-p*1/4
Any idea what should I do next?
Also, I don't really understand what he means for "Show that if
after each move this distribution is preserved, then p = 3/7."
What exactly is the "distribution" refering to? is it N?
How could we use the property that the distribution is preserved