Answer: $6,000,000 
Step-by-step explanation:
Hi, to answer this question we simply have to multiply the total market capital of the company (20,000,000) by the percentage under preferred stock (30%) in decimal form. 
Mathematically speaking: 
20,000,000 x (30/100) = $6,000,000 
Feel free to ask for more if needed or if you did not understand something.