Pedestrian 7570

A pedestrian left town S at a speed of 4.2 km/h. After 1 hour and 10 minutes, a cyclist left the same city and in the same direction at a speed of 18 km/h. After how many minutes does the cyclist catch up with the pedestrian, and how far from town S?

Correct answer:

m =  21.3043 min
s =  6.3913 km

Step-by-step explanation:

$$\begin{gathered} 4.2\cdot (t+(1+10/60))=18\cdot t \\ 828t=294 \\ t=\frac{294}{828}=0.35507246 \\ t=\frac{49}{138}\doteq 0.355072 \\ m=60\cdot t=60\cdot 0.3551=21.3043\text{min} \end{gathered}$$

$s=18\cdot t=18\cdot 0.3551=6.3913\text{km}$

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