Can a 40000mah power bank charge a laptop?

Can a 40,000mAh power bank charge a laptop? Well, should it? Theoretically, yeah! I mean, 40,000mAh is a beast, right? My laptop battery isn't that big. I'm thinking it should juice it up at least twice, maybe even three times? That would be amazing, especially when I'm traveling, you know? No more hunting for outlets at the airport – bliss!

But... and there's always a "but," isn't there? I'm always a little nervous. Like, what if it doesn't live up to the hype? What if it takes like, twelve hours to charge my laptop once? Ugh, I've had power banks that promised the world and delivered… well, not much. Remember that one, the silver one? Total dud. Claimed it could charge my phone like five times. Two, maybe, if I was lucky. And it took forever.

So, yeah, I'm seeing these claims of 2-4 charges for this 40,000mAh one, and it sounds plausible. But I'm definitely the "I'll believe it when I see it" type. I'd need to test it out myself, really put it through its paces, before I'd fully trust it on a long trip or something. Wouldn't you?