Answer:
[tex]1.86\cdot 10^{-4} mi[/tex]
Explanation:
Light travels at constant speed, so we can use the formula
[tex]d=vt[/tex]
where
d is the distance travelled
[tex]v=186000 mi/s = 1.86\cdot 10^5 mi/s[/tex] is the speed of light
[tex]t=1ns=1\cdot 10^{-9}s[/tex] is the time we are considering
Substituting the numbers into the formula, we find
[tex]d=(1.86\cdot 10^5 mi/s)(1\cdot 10^{-9} s)=1.86\cdot 10^{-4} mi[/tex]