Can I convert binocular zoom to equivalent lens focal length?

I read another SE post that shows how focal lengths can be converted to optical magnification, but it isn't clear to me how it would work the other way around. My binoculars are adjustable from x10 to x30 times zoom, but what would that be in an equivalent lens focal length? Working with the equation you have some reference focal lengths to work off of, but working with magnification it is not clear to me what information to use. Would I use the focal length of the human eye as the minimum focal length, the optical zoom as the magnification number, and the maximum focal length would be what I'm solve for?