A man I know travels to Chinsura everyday for his work. His wife drives him over to Howrah station every morning and in the evening exactly at 6.00 pm she picks him up from the station and takes him home.

One day He was left off at work an hour earlier and so he arrived at the Howrah bridge at 5:00 pm instead of 6 and started to walk back home however, he met his wife in the route and got into the car. They drove back home arriving 10 minutes earlier than usual.

How long did the man have to walk before he was picked up by his wife?