Initial velocity = 36 km/h = 36 * 1000 m / 3600 s = 10 m/s
Final velocity = 72 km/h = 72 * 1000 m / 3600 s = 20 m/s
time = 25 seconds
Acceleration = (20 - 10) / 25
= 10 / 25 = 0.4 m/s2.