Gardial GreenLights, a manufacturer of energy efficient lighting solutions, has had such success with its new products that it is planning to substantially expand its manufacturing capacity with a $15 million investment in new machinery. Gardial plans to maintain its current 30% debt-to-total-assets ratio for its capital structure and to maintain its dividend policy in which at the end of each year it distributes 55% of the year's net income. This year's net income was $8 million. How much external equity must Gardial seek now to expand as planned