Susan started an electric bicycle company with her savings of $200,000. Her new business is successful, and she attracts a $2 million investment from venture capital firm A at a post-money valuation of $5 million. Susan continues to grow her business and meets additional milestones. After seeing that the milestones have been met, venture capital firm A and a new venture capital firm, B, invested a combined $15 million into Susan’s electric bicycle firm at a post-money valuation of $40 million. 

What is Susan’s ownership of the firm after this investment?