I think the math part that i have attached is correct. Please double check my math, give the rate of return, and explain who is correct.

In March 2010 the management team of Londonderry Air (LA) met to discuss a proposal to purchase five shorthaul aircraft at a total cost of $25 million. There was general enthusiasm for the investment, and the new aircraft were expected to generate an annual cash flow of $4 million for 20 years.

The focus of the meeting was on how to finance the purchase. LA had $20 million in cash and marketable securities (see table), but Ed Johnson, the chief financial officer, pointed out that the company needed at least $10 million in cash to meet normal outflow and as a contingency reserve. This meant that there would be a cash deficiency of $15 million, which the firm would need to cover either by the sale of common stock or by additional borrowing. While admitting that the arguments were finely balanced, Mr. Johnson recommended an issue of stock. He pointed out that the airline industry was subject to wide swings in profits and the firm should be careful to avoid the risk of excessive borrowing. He estimated that in market value terms the long-term debt ratio was about 62% and that a further debt issue would raise the ratio to 64%.

Mr. Johnson's only doubt about making a stock issue was that investors might jump to the conclusion that management believed the stock was overpriced, in which case the announcement might prompt an unjustified selloff by investors. He stressed therefore that the company needed to explain carefully the reasons for the issue. Also, he suggested that demand for the issue would be enhanced if at the same time LA increased its dividend payment. This would provide a tangible indication of management's confidence in the future.

These arguments cut little ice with LA's chief executive. "Ed," she said, "I know that you're the expert on all this, but everything you say flies in the face of common sense. Why should we want to sell more equity when our stock has fallen over the past year by nearly a fifth? Our stock is currently offering a dividend yield of 6.5%, which makes equity an expensive source of capital. Increasing the dividend would simply make it more expensive. What's more, I don't see the point of paying out more money to the stockholders at the same time that we are askingthemfor cash. If we hike the dividend, we will need to increase the amount of the stock issue; so we will just be paying the higher dividend out of the shareholders' own pockets. You're also ignoring the question of dilution. Our equity currently has a book value of $12 a share; it's not playing fair by our existing shareholders if we now issue stock for around $10 a share.

"Look at the alternative. We can borrow today at 5%. We get a tax break on the interest, so the after-tax cost of borrowing is .65 5 = 3.25%. That's about half the cost of equity. We expect to earn a return of 15% on these new aircraft. If we can raise money at 3.25% and invest it at 15%, that's a good deal in my book.

"You finance guys are always talking about risk, but as long as we don't go bankrupt, borrowing doesn't add any risk at all. In any case my calculations show that the debt ratio is only 45%, which doesn't sound excessive to me.

"Ed, I don't want to push my views on thisafter all, you're the expert. We don't need to make a firm recommendation to the board until next month. In the meantime, why don't you get one of your new business graduates to look at the whole issue of how we should finance the deal and what return we need to earn on these planes?"

Evaluate Mr. Johnson's arguments about the stock issue and dividend payment as well as the reply of LA's chief executive. Who is correct? What is the required rate of return on the new planes?