3 in 5

Time for this weeks puzzler.

Here you go.

My friend says to me, "I just read that 3 of the first 5 presidents of the United States died on the Fourth of July. What do you think the odds of that happening are?"

I reply, "I have no idea, but I'll give you 10 to 1 odds that I can name at least one of the three."

Then he says, "I don't know anything about the first five presidents, except that their names are Washington, Adams, Jefferson, Madison and Monroe."

The puzzler question is this.

How am I justified in offering my friend 10 to 1 odds, when guessing randomly, I have only a 3 and 5 chance?

Good luck.

Answer the Puzzler »

Remember last week's puzzler?

The Slow Burn

It is puzzler time again folks.

This is a string puzzler. We have a few of these from time to time. Here it is.

Here we go.

Imagine that you have in your possession two pieces of string. Each piece is a couple of feet long or so. They can be different lengths, that's okay.

They are burnable strings, like fuses or candle wicks.

So in this case, you could light either end of either string, and it would burn.

So, if you lit the end of one string, it would take a whole hour to burn from beginning to end. They are very slow burning fuses, these strings. So, one hour, to burn one string.

However, there's a little wrinkle.

The string does not burn at any constant or predictable rate. For example, it might burn up 90% of the string in the first 5 minutes and then take 55 minutes to get the last piece. The string could speed up its burn rate, or slow down randomly. It is unpredictable. But what you do know is that it would take one whole hour the burn the entire thing.

So all you know for sure is that if you lit one end, the string would be gone in an hour.

The puzzler question is this.

With only a Zippo lighter and these two strings, how would you measure 15 minutes of time?