please explain why

Consider Mark and Lori's offer on the Shark tank clip If they offer $100,000 for a 20% stake, what do Mark and Lori think the entire company is worth? hint: if 20% of the firm is worth $100,000, what is 40% of the firm worth (yes it is $200,000)? What about 60% of the firm (if you answered $300,000 then you are correct)? so finally what about 100% of the firm? O $500,000 $200,000 $100,000 $2,000,000