5. Your father invested a lump sum 18 years ago at 6.25 percent interest. Today, he gave you the proceeds of that investment which totaled $65,460.36. How much did your father originally invest? Show your work.

6. Thirty years ago, your mother invested $4,000. Today, that investment is worth $109,099.26. What is the average annual rate of return she earned on this investment? Show your work.