wife picked husband on 4:50.

Solution: Wife saved 20 minutes of the time. This time was saved as husband covered some distance that wife would cover to meet him at train station. so let say the time saved in covering that distance is "t"

so 20 minutes saved will be twice of "t" as that distance would be covered twice by wife to pick husband.

so t = 10 minutes.

since wife reaches tain station at 5 so in this case she will meet the husband at 5 - 10 minutes = 4:50