Weren't you a Math major? (obviously not a Business major!)

The hotel had $100 in it's "receivables account." (owed by the hooker)

The hooker paid off her debt, but it never got credited to the hotel's receivables account because the tourist took it, even though there was no debt (owed to the tourist) logged in the hotel's "payables" account.

(that said, I'll admit it was cute)