Length of one step while walking is approximately 2 feet or 60 cms. So every step you walk, you cover a distance of 60 cm.
Now, this is easy to remember. You know that a First Class in an exam is 60%. So now you will not forget that one step is 60 cm.
So, if you walk 2500 steps, the total distance covered is 2500 * 60/100 = 1500 metres or 1.5 km
Now, I have made some simplifications here. Actually, each step is a little over 60 cm, but then we are discussing health, not physics. So please bear with me there.
Ok, the next exercise is for you. Find out how much time you require, in minutes, to take 2500 steps. If the time is say, t mins, then you can calculate your walking speed as 1.5/t. That will be your speed in km per minute.
So what do you do with this information? You exercise.
And the next time you have to meet that someone special and have to walk, you can calculate the time required to reach the destination.
Ofcourse, if you have to reach someone very special, two things will happen: (1) your steps will become bigger, as much as 65 to 70 cms each, and (2) your speed of walking will be more. Obviously.