If it had been a typo or just an arithmetic error, I wouldn't have cared (or even noticed). But you also completely confidently declared that the problem had been identified to be c and that the boundary for VR is "city limits". It means that either [1] you have never had a real-time conversation with anyone much farther away to help you sanity-check this result (in which case it's an innocent mistake, and like I said, it's a good excuse to also go out and see the world), or (or possibly "and") that [2] you did not even care to try to think about this topic for 2 seconds before writing about it -- not when you first heard about it wherever you did, nor when you wrote about it here to teach it to other.

Whatever the larger issue, the silly math error is 100% beside the point... you could've written light-years for all anyone cared, and forgotten about it the day after. However, the underlying issue is not the kind of problem to forget about the next day. Lots of alarm bells should be going off in your mind that you need to actively do something to correct whatever the root problem is (which I was trying to help you identify), because otherwise you'll keep actively making the world (and HN) a worse place with this kind of misinformation, and that is something I'm tacitly assuming you don't want to do.

So: please, please, please ensure put 1-2 seconds of thought into sanity checking whatever you write in the future -- especially it's too painful to at least qualify what you write with an "I think" so that readers realize you're deriving your own conclusion and not propagating an established fact. We have enough problems in this world with the spread of misinformation that hinges on subtle nuances that we don't also need to put up with problems that should be pretty easy to spot from light-years away.