Quote: Nelson charged $542.95 for a new printer on May 12 and $56.79 for a restaurant bill on May 22. Calculate the interest charged, at 19.5% simple interest, on the payment date of June 21st.
(RECALL: I = PrT)
Okay, so I am having troubles figuring out how to calculate this. Examples I have are helpful to a point, but unfortunately do not show me exactly what to do. :/ Please help.