Tom Hoofs it Home

RAY: Here's the answer: Tom was walking for 50 minutes before his wife picked him up. They arrived home 20 minutes earlier than usual, so by walking he saved 10 minutes of her travel time to the station and 10 minutes of her travel time home from the station. Therefore, he was walking for 50 minutes when she picked him up. It's as if he moved the station 10 minutes closer.

TOM: Pretty good of me, eh?

[ Car Talk Puzzler ]