Answer:
preferred stocks = 2,500 stocks x 4% x $50 par value = $5,000 preferred dividends per year
common stock = 50,000 stocks outstanding of $1 par value
in 2017, $3,000 in dividends are distributed, all to preferred stocks
In 2018, $18,000 in dividends are distributed, $7,000 to preferred stock ($2,000 cumulative from last year and $5,000 from this year) and $11,000 are distributed to common stockholders.
In 2018, each preferred stock received = $7,000 / 2,500 stocks = $2.80 per preferred stock. Each common stockholder received $11,000 / 50,000 = $0.22 per common stock.