4. Profits: Retail Jobs and productivity. How do retail stores rate? One way to answer this question is to examine annual pronts per employee. The following data give
annual profits per employee (in units of one thousand dollars per employees for
companies in retail sales. See reference in Problem 3. Companies such as Gap,

For one thing, you need that formula solved for years.
Also, for continuously compounded interest, a different formula is needed. It is located here:
http://www.1728.org/rate2.htm

Years = ln (total / principal) / rate
Years = ln (5,000 / 50) / .05
Years = ln (100) / .05
Years = 4.605170186 / .05
Years = 92.10340372
Years = 92.10 (rounded)

Here's a calculator to check that:
http://www.1728.org/compint.htm