Предмет: Алгебра, автор: kanorie

первые четыре часа автомобиль ехал со скоростью 65 км в час следующие два часа со скоростью 90 км в час, а затем два часа со скоростью 60 км в час. найдите среднюю скорость автомобиля на протяжении всего пути.

Ответы

Автор ответа: rokfeller007

4*65=230 - в I 4ч расстояние

2*90=180 - в II 2 ч расстояние

2*60=120 в III 2ч расстояние

260+180+120=560км - все расстояние

4+2+2=8ч -все время

Ucр=все расстояние / все время

Uср=560/8=70 км/ч

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