please help and explain. i don't understand the in arrears calculations needed for this

Dividends Per Share Sandpiper Company has 30,000 shares of cumulative preferred 1% stock, $50 par and 50,000 shares of $20 par common stock. The following amounts were distributed as dividends: Year 1 $37,500 Year 2 7,500 45,000 Year 3 Determine the dividends per share for preferred and common stock for each year. Round all answers to two decimal places. If an answer is zero, enter 'o'. Year 1 Year 2 Year 3 Preferred stock (Dividends per share) $ Common stock (Dividends per share) $