The story of 100 meters race
A, B and C race each other in a 100 meters race. All of them run at a constant speed throughout the race.
A beats B by 20 meters.
B beats C by 20 meters.
By how many meters does A beat C?
If you answer this problem with simple feeling, you will make a mistake. Let’s think about it.
The answer is not 40 meters!
The problem is when A has arrived 100m, B arrived 80m and how about C? Off course, C is not at the point of 60 m.
By the formular of time = distance / speed.
> A beats B by 20 meters
100m/Va = 80m/Vb (formular 1)
> B beats C by 20 meters
100m/Vb = 80m/Vc (formular 2)
> When A got final line at Ta, we have:
100m/Va = 80m/Vb = Dc/Vc (formular 3)
80/100 * 80/Vc = Dc/Vc (applied formular 2 to formular 3)
64m/Vc = Dc/Vc
Dc = 64 m.
> A beats C by 36 meters, this is the correct answer.
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