S1=40*2/3
S2=20 *1/3
80/3+20/3/1/3+2/3=100/3
(2/3*40см/с+1*20см/с)/3=(80/3+20/1)/3=(80+60/3)/3=(140/3)/(3/1)=140/9 см/c=примерно 15.5 см/c
S1=40*2/3
S2=20 *1/3
80/3+20/3/1/3+2/3=100/3
(2/3*40см/с+1*20см/с)/3=(80/3+20/1)/3=(80+60/3)/3=(140/3)/(3/1)=140/9 см/c=примерно 15.5 см/c