On January 1st, Langen Co. declared dividends of $15,000. It was recorded on January 10th. The amount that was due to the preferred stockholders was not paid in full in the previous year when the dividends were paid, and because the preferred stockholders of Langen Co. also have preferred stock that is cumulative, they will receive $8,000. A portion of the $8,000 will be applied to the past. The last time a dividend was paid, the preferred stockholders collected $1,500 less than what would have made everything even out to be equal.  

what the ex-dividend and the dividend dates are in the following scenario?