The cash balance in Roger's account with his stockbroker earns interest on the daily balance at 4% per annum payable on June 30 and December 31. His cash balance on January 1 was $3347. As a result of the purchase or sale of securities from time to time, the balance changed to $8687 on March 4, to $2568 om May 24, and to $5923 on June 17. What interest was credited to Roger's account on June 30 ? The brokerage firm includes interest for both January 1 and June 30 in the June 30 payment. Assume that Febuary has 28 days.