For an uniformly accelerated motion, the following relationship can be used:

where a is the acceleration, S the distance covered, vf the final speed and vi the initial speed.
Before using the formula, we need to convert everything into SI units.
The distance covered is:

To convert the speed from km/h to m/s, let's keep in mind that


so

is the conversion factor.
So the speeds are:


and so, now we can re-arrange the formula to find a, the average acceleration:
