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

I’m trying to explain this in a way that will be intuitive.

Think about watching a video at 1.5x speed, and that after the video ends it keeps playing just showing a blank screen. If you watch that video at the 1.5x speed for the amount of time you would normally watch, you will have seen the whole video plus half the video duration in blank screen.

Now if you consider what you watched as a whole, 33% of it was blank screen. You watched the first half of the video, the second half, then half the duration in blank screen. So of the time you needed to watch the video at normal speed you have reduced it by 33% since you can skip the blank screen time.