Question

The speed of light is about 3x10^8 m/s what is the speed of light in kilometers per hour

Answer 1

$3*10^8 \frac{m}{s} \\\\ 1m\to 10^{-3}km \\\\ 1s\to 36*10^{-4} h \\\\\\ 3*10^8* \frac{10^{-3}km}{36*10^{-4}s}= 10^8 * \frac{10^{-3}*10^4km}{12s}= \\\\ =10^8* \frac{10m}{12s}= \\\\ =10^8* 83*10^{-2} \frac{m}{s}=\\\\= \boxed{83*10^6 \frac{m}{s}}$

Answer 2

$3\cdot10^8 \ \frac{\big{m}}{\big{s}} =3\cdot10^5\cdot \frac{\big{10^3\ m\cdot 3600}}{\big{3600\ s}} =3\cdot10^5\cdot \frac{\big{3600\ km}}{\big{1\ hr}} =108\cdot10^7\ \frac{\big{km}}{\big{hr}}=\\\\=1.08\cdot10^9\ \frac{\big{km}}{\big{hr}}$