The thinking distance is the distance travelled after you notice some danger and you apply the brakes. To get it we have to remember that the distance is given by:
where v is the speed and t is the time. Before we can use this formula we need to convert the velocity from mph to mps, let's do this:
This means that we travel 1/90 mps; now that we have this we use the formula for the distance:
Therefore, the thinking distance is 0.022 miles.