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

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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.

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29 Answers

Anonymous 0 Comments

It’s sometimes easier to imagine with bigger %s.

Watching at speed X 2.0 decreases the time by 50%. Speed is 2, time taken is 1/2.

Watching at speed X 1.5 decreases the time to watch by 33%. Speed is 3/2, time taken is 2/3.

Watching at speed X 1.25 decreases the time to watch by 20%. Speed is 5/4, time is taken 4/5.

Saying +25% speed should decrease the time by 25% is like saying +100% speed should decrease the time by 100%. If that was how it worked, watching it at double speed would result in the video ending instantly.

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