If you drive the first 80 miles of a 200 mile trip at a rate of 64mph and the reminder of the trip at a rate 50mph, what is your average speed for the entire trip ?
\(T= \dfrac{80}{64} + \dfrac{200-80}{50} = \dfrac{5}{4}+\dfrac{12}{5} = \dfrac{73}{20}\)
\(\bar{v} = \dfrac{200}{\frac{73}{20}} = \dfrac{4000}{73} \approx 54.8 ~mph\)
