(A)

I am thinking about putting solar panels on my house. I have estimated that I can save $43/month on my utility bill. If my required rate of return is 7.5% and the useful life of the panels is 15 years, what is the NPV based on an initial cost of $5,500?

(B)

Let's assume that the initial investment is $9,500. What would my monthly savings have to be to make this a profitable investment?