if a particle starts with zero velocity at some point and travels with someconstant acceleration for 100 seconds and then travels with uniform velocity for 5 mins and then decelerates at a constant rate for 150 seconds. find the acceleration, constant velocity and deceleration?

 i  think the question isc in complete

from the graphical interpretation of your data i feel that the following are missing:

1. the final velocity is zero 

2. the distance travelled.

from the data given we can find the ratio between the magnitudes of the acceleration and the deceleration. we cannot find the constant velocity. this can be done only if it is assumed that the final velocity is zero. we require to know the distance travelled also.