Manuel traveled 31 hours nonstop to Mexico, a total of 2,300 miles. He took a train part of the way, which averaged 80 mph, and then took a bus the remaining distance, which averaged 60 mph. How long was Manuel on the train?
rate * time = distance
train time = t
bus time = b = 31 hrs - t
80 * t + 60 (31 - t) = 2300
80t + 1860 - 60 t = 2300 solve for 't' the train time