I guess it is obvious that the sample and some of the test are COMPLETELY WRONG. Does anybody have an idea where does the sample answer come from? Any ideas that you'd like to share?

I promise it is obvious that the sample and all of the test are COMPLETELY RIGHT . Maybe you misunderstood it . Notice that the money got from the companies is the "net profit", in other words,it's R-T(R)+R*L%-T(R*L%).So you should calculate R first according to the rules.