> Is 70ms 14 or 12% faster than 80ms ?
Times: t vs T, t = (1 - s)T, meaning t is s x 100% shorter than T.
Speeds: v = 1/t vs V = 1/T, v = (1/(1 - s)) V = (1 + f)V, meaning v is f x 100% faster than V.
Obviously 1/(1 - s) = (1 + f), so f = s / (1 - s), and s = f / (1 + f).
With t = 70 and T = 80, s = 0.125, f = 0.143.
> If the math is right, it is impossible to be 100% faster.
Given f = 1 and T = 80, s = 0.5, t = 40.
Cheers,
V.