KöMaL 2010 K235

The official currency on the planet Kloppar is the tirof, for which the small change is the dimar, and there is an even smaller change called the nepi. One dimar is worth a whole number of nepis, and a tirof is worth a whole number of dimars. Sangi had dinner in a restaurant on the planet. After dinner he received the following bill: Fried vondar: 7 dimars and 2 nepis; Pickled rotins: 10 dimars and 5 nepis; Vundeg bread: 1 dimar and 6 nepis; Carbonated nestaki drink: 6 dimars and 4 nepis; Krabban cake: 4 dimars; Total: 2 tirofs, 8 dimars and 1 nepi. How many dimars are worth a tirof, and how many nepis are worth a dimar?