Two calculator exam problems

[Peter Murphy]

Carl, the Prime seems ideally suited for such problems.

Can you (or anyone) show me how to set up and solve them on a 50g (in RPN mode) or a 48G? I've puzzled over this for a good while.

The concept of the user-defined function (UDF) for the 48/50 calculators seems promising, but what I've done hasn't produced the structure that you exhibit in your Prime examples.

I now find that David Hayden solved such a problem (problem 13) back in 2009:

[url:http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv019.cgi?read=159915]

but he's taking for granted what I cannot see at all, namely how one sets up such nested functions in the first place.