RAY: Back in the old days when my brother used to work, my brother used to have his wife drive him to the train station and then he'd take the train and go to work. Then an hour later, he'd get on the train to come home.

TOM: After lunch.

RAY: Right after lunch. And he'd get to the train station and his wife would meet him there and they'd drive home. Well one day, he decides to leave work early at 11 am. Needless to say, he gets to the train station an hour early. Rather than call his wife, it's a nice day and he decides to hoof it. So he starts walking in the direction she'll be driving. And low and behold, he sees his wife coming up the road and she sees him by the side of the road. They get in the car and they drive home and arrive 20 minutes earlier. Don't forget - she left home at the usual time.

TOM: Of course, she didn't know he was going to leave work an hour early.

RAY: They get home 20 minutes earlier than they would have gotten home. How long was he walking before they met? Notice, there's no mention of how long she was driving, how fast he walked, what train he took, and what any of the distances were. How long was he walking before she picked him up?