On a straight road, a car starts from rest and accelerates at uniform rate of 6 m s-2 for some time, then moves with constant speed for some time and retards at the same uniform rate and comes to rest. Total time for the journey is 24 s and average speed for journey is 20 m s-1.
How long does the car move with constant speed?
B 8 s
C 12 s
D 16 s
answer given is wrong