Alight-rail train going from one station to the next on a straight section of track accelerates from rest at 1.1 m/s2 for 20 s. it then proceeds at constant speed for 1100 m before slowing down at 2.2 m/s2 until it stops at the station.
how much time does it take the train to go between the stations?
express your answer using two significant figures.

-- Accelerating for 20 seconds takes it 20 seconds.
During that time, it reaches aspeed of  (1.1 x 20) = 22m/s .

-- Moving at 22 m/s, it takes  (1100 / 22) = 50 seconds to cover 1100 m.

-- To go from 22 m/s to a stop takes  (22 / 2.2) = 10 seconds .

Total time = (20 + 50 + 10) = 80 seconds.

The slightly-more-interesting question concerning the same train is:
What is the total distance between the two stations ?