Speed = (rate of acceleration) x (time)
Accelerating at 5.5 m/s² for 4 seconds, the car gains (5.5 x 4) = 22 m/s of speed.
If it's actually traveling at 25 m/s at the end of that time, then it must have already been moving at (25 - 22) = 3 m/s when the 4 seconds started.
