Light travels at precisely <span>299,792,458 metres every second (abbreviated to 3 x 10^8 metres every second but let's be precise)
There are 60 seconds in every minute (</span><span>299 792 458 x 60 = 17,987,547,480m)
60 minutes in every hour (17,987,547,480 x 60 = 1,079,252,849,000m)
96 hours in 4 days (</span><span>1,079,252,849,000 x 96 = 10,360,827,350,000m)
</span><span>Now let's convert to km to make this number (slightly) more manageable
(</span>10,360,827,350,000 / 1000 = <span>103,608,273,500km)
</span>Light travels <span>103,608,273,500km in 4 days - that's the equivalent of going around the equator of the earth 813,124 times!</span><span>
</span>
Answer:
30, 50
Explanation:
Hello,
In this since an element's atomic number is equal to the number of protons in its atom, we can infer that selenium's atomic number is 30. Moreover, due to the fact the the neutrons are equal to the atomic mass minus the atomic number or the number of protons, by knowing the number of neutrons we compute the atomic as follows:

Thus, answer is 30, 50.
Best regards.