## Wednesday, June 19, 2013

### Wednesday Brain Teaser 6-19-13

I think my one last week was too hard.  I'll provide the answer as soon as I can find it...I'm trying to remember which book I got it out of.

Anyway, here's an easier one:

A car travels at a speed of 50 mph over a certain distance, and then goes 30 mph over the same distance on the way back.  What's the average speed for the trip?

1. I'm getting 37.5 miles per hour...

2. The answer to last week's puzzle:

3+(69258/714)
81+(5643/297)
81+(7524/396)
82+(3546/197)
91+(5742/638)
91+(5823/647)
91+(7524/836)
94+(1578/263)
96+(1428/357)
96+(1752/438)
96+(2148/537)

3. Last week's didn't seem so much hard as tedious. I would have bit for a version that said "There are ten solutions. Nine start with a whole number greater than 80. Which one doesn't?"

As for today's, as the answer is the same for any distance, you can just pick one. I pick 50 miles, which results in traveling 100 miles in 2 hours and 40 minutes, which does indeed equal 37.5mph. The initial impulse is to just guess 40. But it's a puzzle, so you know that's going to be wrong...