t = \frac{s}{v} = \frac{s}{c} = \frac{3000 m}{300 \frac{M m}{s}} = \frac{3000 m}{300 \frac{m}{μ s}} = 10 μ s

${t=\frac{s}{v}=\frac{s}{c}=\frac{3000\,m}{300\,\frac{Mm}{s}}=\frac{3000\,m}{300\frac{m}{\mu s}}=10\,\mu s}$

Error