How long is thirty km in minutes?

Answer 1

It would appear you are mixing units, that is measures of distance and measures of time. However, it may be that you are referring to "light minutes", as such measure distance as well.

Given that the speed of light in a vacuum is 299,792,458 per second, this would mean that one light minute would be 17,987,547,480 kilometers.

We can readily see by this that such a small distance as thirty kilometers could only be expressed in a fraction of a light minute, and indeed would be only a fraction of a light second.

If we take 299,792,458 kilometers and divide it by 30 kilometers, we see that 1/9,993,082th of a light second is about thirty kilometers.

Therefore, in answer to "How long is thirty kilometers expressed in light seconds?", the answer is roughly 1/10 millionth of a light second.