I'm once again working on the tutorial from University of Waterloo (http://cscircles.cemc.uwaterloo.ca/2x-extra-practice/). It's very important to remember to log in before continuing with this site! Otherwise, your progress is not remembered.
I am on the 2X: Extra Practice section, now. I had to travel for work last week, so I haven't been able to work on this as much. It is coming back to me pretty quickly, though.
I had trouble with Payment Calculator. I thought I had the right answer, but apparently not. I contacted the school using the HELP link, and I was surprised that I actually got a response back in a couple of days! I really wasn't expecting one, especially during the summer session. So, I'm working on this, now. Hopefully, I'll get it figured out.
Meanwhile, Mufasa, my baby kitty, is attacking my feet, making concentration difficult. I need coffee!