Why does watching a video at 1.25 speed decrease the time by 20%? And 1.5 speed decreases it by 33%?

Question

I guess this reveals how fucking dumb I am. I can’t get the math to make sense in my head. If you watch at 1.25 speed, logically (or illogically I guess) I assume that this makes the video 1/4 shorter, but that isn’t correct.

In short, could someone reexplain how fractions and decimals work? Lol

Edit: thank you all, I understand now. You helped me reorient my thinking.

In: 8653

Answer 1

If you went 2.00 times faster, would you expect to get there instantly? No, instead, it’s half the time. When you go X times faster, you reduce the time to 1/X. So 2 times faster makes the time 1/2 what it was. 5 times faster, you’d get there in 1/5th the time. 1.25 times faster can be expressed as 5/4 times faster, and you get there in 4/5th the time, or 80%.