Question

a car accelerate uniformly from rest at 5.0 ms^2 until it reaches a speed of 20 ms^2. it travels at this speed for 40 seconds. then brakes are then applied and the car came to a rest with a uniform retardation in a further 8.0 seconds.

Answer 1

v = v0 + at

s = v0t + 1/2 at^2
You didn't ask any question, but those formulas will be of use.