Fido Rescue is building a new kennel and investing in new equipment. The kennel will cost $300,000 to build, and will last 20 years. It is expected that at the end of this period, it will be torn down and will have no remaining value. The associated equipment is expected to cost $50,000 and will have a useful life for the agency of 10 years. At that point it can be sold for 10 percent of its original value (for now, ignore discounting). Please show the mathematics used to calculate the answer to 10. Write out all steps and arithmetic formulas in detail.