"have you noticed," he said "that the McDonalds signs seem to be evenly spaced along the side of the road? i wonder how far apart they are"

Mrs Simpson glanced at her watch, then counted the number of mcdonalds signs they passed in one minute.

What a strange coincidence" exclaimed bart, "when you multiply the number by 10 it is exactly equal to the speed of our car in km/h (kilometers per hour)

Assuming that the car is traveling at a constant speed and the minute began and ended midway between the 2 signs, how far is it between one sign and the next?

I have the answer, it's 166.67 meters, found by:

Suppose they pass 6 signs, so the speed is 60km/h

therefore 1km/minute

1km/6signs=0.16(repepater) km

try with 8, 10,200, all equals the same in the end.

So, my question is, how do i write this algebraically, what is the formal method?