The test driver drove from Ostrava to Warsaw at an average speed of \(66\, \mathrm{km}/\mathrm{h}\) and the journey took him \(6\) hours. After him, the same route took several other drivers. (Each driver took a different driving time.) Choose the function giving the average speed \(v\) of each of these drivers as a function of the total driving time \(t\) from Ostrava to Warsaw.