Puzzle – Birthday pairings

Friday, April 30th, 2010

Here's two classic birthday puzzles: How many people do you need in a room to have a better than 50% chance of finding at least one shared birthday among them? [ddet Answer] Like a lot of these problems, it's easier to first find the chances of the proposition not happening - ...

The “Mathematical Constant” and Continuously Compouding Interest

Sunday, June 8th, 2008

One of the (many) aspects of the "Mathematical Constant" $$e$$ is that: $$\lim_{x\to\infty} (1+\frac{1}{x})^x = e$$ This property makes $$e$$ very useful for working on compounding interest problems. How so? Let's start with the basic time value of money formula giving the relationship between the PV (present value) and FV (future value) given R (the ...