Лодка проплыла расстояние между пристанями вниз по течению течению реки и вернулась обратно, затратив на весь путь 5 ч. собственная скорость лодки 10 км/ч, скорость течения реки 2 км/ч. сколько времени лодка плыла по течению реки. составьте уравнение обозначив через х время, которое лодка плыла по течению реки. !

х - время, которое плыла лодка по течению реки

10+2=12 (км/ч) - скорость лодки по течению

10-2=8 (км/ч) - скорость лодки против течения

12*х=8*(5-х)

12х=40-8х

12х+8х=40

20х=40

х=40: 20

х=2 (ч)

ответ: 2 часа лодка плыла по течению реки 

по течению лодка проплыла

(10+2)х

а против течения:

(10-2)(5-х)

(10+2)х=(10-2)(5-х)

12х=40-8х

х=2ч

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