Дано:
v0 = 300 км/ч
t1 = 2.2 ч
t2 = 2.4 ч
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v(в) - ?
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t1 = S/(v0 + v(в))
t2 = S/(v0 - v(в))
t2/t1 = (v0 + v(в)) / (v0 - v(в))
(v0 + v(в)) = (v0 - v(в)) *(t2/t1)
v(в) * (1 + t2/t1) = v0 * (t2/t1 - 1)
v(в) = [v0 * (t2/t1 - 1)] / (1 + t2/t1)
v(в) = 300 * (2.4/2.2 -1) / (1 + 2.4/2.2) = 300 * [(1/11):(13/11)] = 300/13 = 23.077 км/ч