Marcus was traveling 11 hours before Marie caught up.
Step-by-step explanation:
Let the time of travel of Marcus before they caught up be t.
Time of travel of Marie = t - 2
Speed of Marcus = 45 mph
Speed of Marie = 55 mph
Distance traveled by them will be same.
Hence
Speed of Marcus x Time of travel of Marcus before they caught up= Speed of Marie x Time of travel of Marie before they caught up
 45 x t= 55 x (t-2)
 45t= 55 t - 110
 10 t = 110
 t = 11 hours
Marcus was traveling 11 hours before Marie caught up.