Предмет: Алгебра, автор: dmitrii151

Моторная лодка прошла 58км по течению реки и 42км против течения за то же время что она проходит 100км в стоячей воде.Найдите скорость лодки в стоячей воде если скорость течения равна 4км/ч

Ответы

Автор ответа: Julia1508

Пусть х км/ч - скорость лодки, скорость лодки в стоячей воде

Составим уравнение:
58 : (x+4)+42 : (x-4)=100 : x
58x * (x - 4) + 42x* (x + 4) - 100* (x^2 - 16) = 0

58x^2 - 232x + 42x^2 + 168x - 100x^2 - 1600 = 0

...
x=25
Ответ: скорость лодки в стоячей воде = 25 км/ч.

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