Delta Corporation has the following capital structure:

	Cost (aftertax)			Weights			Weighted Cost
Debt (Kd)		7.5	%		15	%		1.13	%
Preferred stock (Kp)		6.2			10			0.62
Common equity (Ke) (retained earnings)		8.5			75			6.38
Weighted average cost of capital (Ka)								8.12	%

a. If the firm has $48 million in retained earnings, at what size capital structure will the firm run out of retained earnings? (Enter your answer in millions of dollars (e.g., $10 million should be entered as "10").)

b. The 7.5 percent cost of debt referred to earlier applies only to the first $15 million of debt. After that the cost of debt will go up. At what size capital structure will there be a change in the cost of debt? (Enter your answer in millions of dollars (e.g., $10 million should be entered as "10").)