## Twittering about Math

I've gotten excited about using twitter for VERY short snippets of fun Math stuff. I've started twittering URLs of cool Math sites.

If you're interesting in following my tweets, not all will be about Math, my twitter name is slederman.

If you twitter a fair amount about Math leave your twitter name in the comments and I'll follow you.

## MMM #19: Two winners!

We had 25 submissions for MMM #19 so I decided to give out two prizes! Random.org picked the numbers 6 and 22, which corresponded to the entries from Patrick Swickard and Todd Trimble. Congratulations to the two of you! I'll be contacting you to get you your prizes!

Everyone who submitted an entry got the right answer, which I would expect since a quick calculator check would verify the answer. Some people explained their answers better than others. The most-straightforward solution I saw was this one by Ron Frederick.

## MMM #19: Which is larger?

Troy Williams was announced as the winner for MMM #18 over at Blinkdagger. Congratulations, Troy!

Now it's time for MMM #19.

I have a Rubik’s Revolution, courtesy of Techno Source (or $10 Amazon.com gift certificate, if you prefer, or $10 in USD via PayPal to non-US folks) to give to the winner.

## A simple but disturbing Math problem

My brother gave me a Math problem this morning. He and I both know how to solve it but we're both disturbed by the fact that the right answer seems unintuitive. I'm interested to see if one of you can explain the answer in a way that **is** intuitive.

Here's the problem: A car gets 50 miles per gallon for a 10 mile stretch of a trip and 40 miles per gallon for the next 10 mile stretch of the trip. What's the average miles per gallon for the two stretches of the trip?

Again, the point isn't to get the right answer. Go ahead and solve it, though, for your personal satisfaction. The point is how one can see that the answer isn't 45 miles per gallon.

Thoughts?