If we use the simple interest formula I=PrT, the principle (P) would be 6000. Assuming that it is based on annual interest, the time (t) would be 1/12. Then, you multiply 6000 by 1/12 to get 500. Finally you divide 192/500 and then multiply by 100.
If the time is based on monthly payments, then do the same thing, except multiply 6000 by 1
