Sparks Corporation has 3,000 shares of 8%, $100 par value preferred stock outstanding at December 31, 2017. At December 31, 2017, the company declared a $105,000 cash dividend ...

We can assume that Sparks Corporation is going to pay preferred stockholders first:

preferred stock dividends = $100 x 8% x 3,000 = $24,000

If the corporation doesn't owe any previous dividends to preferred stockholders, then the remaining $81,000 ( = $105,000 - $24,000) should be distributed to common stockholders.

Each preferred stock will receive a $8 dividend. I don't know the amount of outstanding common stock, so it is not possible to determine how much dividend will be distributed for each common stock outstanding.