Your buddy in mechanical engineering has invented a money machine. The main drawback of the machine is that it is slow. It takes one year to manufacture $ 900. However, once built, the machine will last forever and will require no maintenance. The machine can be built immediately, but it will cost $ 900 to build. Your buddy wants to know if he should invest the money to construct it.
If the interest rate is 7.0 % per year, what should your buddy do?
What is your advice if the machine takes one year to build?
The NPV of the machine is $