Given that sigma motors has assets of $500000, liabilities of $1,200,000 and retained earning of $1,500,000.
If we subtract liabilities from assets, we will get stockholder equity.
That is stockholder equity = 5000000-1200000
=$ 3800000
Let common stock be x.
If we subtract common stock from stockholder equity, we will get retained earnings.
That is stockholder equity - common stock = retained earnings
3800000 - x = 1500000
x=3800000-1500000
x = $2300000
Hence value of common stock = $2300000
