Dane:

$v_1=20\frac{km}{h}$  

$v_2=15\frac{km}{h}$

${\alpha }_1={30}^{\circ }$  

${\alpha }_2={60}^{\circ }$  

$d=200km$  

Szukane:

$t_1\stackrel{?}{=}{t}_2$