Answer :
(a) The acceleration of the car is, 
(b) The distance covered by the car is, 150 m
Explanation :
By the 1st equation of motion,
...........(1)
where,
v = final velocity = 5 m/s
u = initial velocity = 25 m/s
t = time = 10 s
a = acceleration of the car = ?
Now put all the given values in the above equation 1, we get:


The acceleration of the car is, 
By the 2nd equation of motion,
...........(2)
where,
s = distance covered by the car = ?
u = initial velocity = 25 m/s
t = time = 10 s
a = acceleration of the car = 
Now put all the given values in the above equation 2, we get:

By solving the term, we get:

The distance covered by the car is, 150 m