Предмет: Математика, автор: absdvzscbbc

Лодка 8 часов плыла по течению реки.
Собственная скорость лодки составляет 9,83 км/ч,
а скорость течения реки 7,32 км/ч. На какое
расстояние отплывет лодка?

Ответы

Автор ответа: sulymaanna2011
1

Відповідь:

s = v * t – формула шляху

х (км/год) – власна швидкість човна

х + 2 (км/ч) - швидкість човна за течією річки, t = 8 год - час у дорозі

х - 2 (км/ч) - швидкість човна проти течії річки, t = 5 год - час у дорозі

Рівняння: (х + 2) * 8 = 2 * (х - 2) * 5

                   8х + 16 = 10х - 20

                   10х - 8х = 16 + 20

                   2х = 36

                   х = 36: 2

                   х = 18

Відповідь: 18 км/год – власна швидкість човна.

Перевірка: (18 + 2) * 8 = 2 * (18 - 2) * 5

                  20*8 = 2*16*5

                  160 = 160

Покрокове пояснення:

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