Bike meeting

John and William agreed that on Saturday at 7:00 AM, they would go on a trip on their bikes. John fell asleep and started an hour later. When and where will the friends meet? We know that William walked at an average speed of 15 km/h and John at 25 km/h.

Result

s =  37.5 km
x = 9:30 hh:mm

Step-by-step explanation:

$$\begin{gathered} v_1=15\text{km/h} \\ {v}_2=25\text{km/h} \\ d=1\text{h} \\ {s}_1=s_2 \\ {v}_1\cdot t=v_2\cdot (t-d) \\ 15\cdot t=25\cdot (t-1) \\ 10t=25 \\ t=\frac{25}{10}=2.5 \\ t=\frac{5}{2}=2.5 \\ s=v_1\cdot t=15\cdot 2.5=37.5\text{km} \end{gathered}$$

$x=7.00+t=7.00+2.5=\frac{19}{2}=9.5=9:30\text{hh}:\text{mm}$

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