Rainman and BMAD were out for a walk the other day when they came across some barracades along a parade route that blocked their path.
So much for that, mused BMAD, it looks like we either turn back or wait to watch a parade.
I've got a puzzle idea, replied Rainman. Let's measure how long the parade is. When it arrives, you start walking slowly alongside it, and I'll do the same, but in the opposite direction. When I get to the end of the parade I'll stop. When the end of the parade catches up to you, you call my cell phone. BMAD agreed.
When BMAD made the call, she had walked 12 blocks. Rainman reported that he had walked only a third as many. Assuming all speeds were constant, and Rainman and BMAD's speeds were the same, how long was the parade?