What is the total differential cost regarding the decision to buy the model 200 machine rather than the model 300 machine

The common stock and debt of northern sludge are valued at $65 million and $35 million, respectively. investors currently require a return of 15.9% on the common stock and a return of 7.8% on the debt. if northern sludge issues an additional $14 million of common stock and uses this money to retire debt, what happens to the expected return on the stock? assume that the change in capital structure does not affect the interest rate on northern’s debt and that there are no taxes.