Rita takes a train home at $$4.00$$, arriving at the station at $$6.00$$. Every day, driving at the same rate, her husband meets her at the station at $$6.00$$. One day she takes the train an hour early and arrives at $$5.00$$. Her husband leaves home to meet her at the usual time, so Rita begins to walk home. He meets her on the way and they reach home $$20$$ minutes earlier than usual. The number of minutes Rita was walking before she met her husband on the way is