Final answer:
The amount of dividends common shareholders will receive in 2021 is $10,000.
Step-by-step explanation:
The amount of dividends common shareholders will receive in 2021 can be calculated by subtracting the dividends paid to preferred shareholders from the total dividends declared by the board of directors. In this case, the dividends paid to preferred shareholders is $40,000 (cumulative preferred stock at 6% par of $400,000), which leaves $10,000 ($50,000 - $40,000) for common shareholders. Therefore, the amount of dividends common shareholders will receive in 2021 is $10,000.