S <span>– расстояние от А до В.</span>
S<span>/3 - скорость первого.</span>
S<span>/6 - скорость
второго.</span>
Время<span> </span>до<span> </span>встречи<span> = S:(S/3+
S/6)= S:S(1/3+ 1/6)= </span>
1: (1/3+ 1/6) = 1:3/6 = 2 <span>часа</span>
I do not understand Ukrainian, can you speak English?
20/21-6/21=(20-6)/21= 14/21
13/18-7/18=(13-7)/18=6/18=1/3