Timetable 3401

The train ran the distance between stations at a speed of 90km/h for 4 hours. What speed can he drive if, according to the new timetable, the journey takes an hour longer?

Final Answer:

v =  72 km/h

Step-by-step explanation:

$$\begin{gathered} v_1=90\text{km/h} \\ {t}_1=4\text{h} \\ s=v_1\cdot t_1=90\cdot 4=360\text{km} \\ v=s/(t_1+1)=360/(4+1)=72\text{km/h} \end{gathered}$$

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