The distance from Paris to San Francisco is 9120 kilometers what is the average speed if the flight is 12 hours and 40 minutes long?
$${\frac{{\mathtt{9\,120}}}{\left({\mathtt{12}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{40}}}{{\mathtt{60}}}}\right)}} = {\mathtt{720}}$$
720 km/hour