prędkość * czas = droga
v * t = s
(v_1+v_2)*30min=60km
v_1*12min+(v_1+v_2)*25min=60km
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30min=\frac{1}{2}h
12min=\not12^1*\frac{1}{\not60^5}h=\frac{1}{5}h
25min=\not25^5*\frac{1}{\not60^{12}}h=\frac{5}{12}h
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układ równań z dwiema niewiadomymi
(v_1+v_2)*\frac{1}{2}=60|*2
\frac{1}{5}*v_1+(v_1+v_2)*\frac{5}{12}=60
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v_1+v_2=120
\frac{12v_1}{60}+\frac{25(v_1+v_2)}{60}=60|*60
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v_2=120-v_1
12v_1+25(v_1+120-v_1)=3600
12v_1+25*120=3600|:12
v_1+25*10=300
v_1+250=300|-250
v_1=50[\frac{km}{h}]
v_2=120-v_1
v_2=120-50
v_2=70[\frac{km}{h}]
v_1=50\frac{km}{h} , v_2=70\frac{km}{h} <-- odpowiedź