Question

собственная скорость лодки равна 9 км в час. Какой должна быть скорость течения реки, чтобы лодка прошла 12 км по течению и вернулась назад не позже сем через 3 часа

Answer 1

х км/ч скорость течения реки

12/(9+х) ч время по течению реки

12/(9-х) ч время против течения реки

12/(9+х) + 12/(9-х)=3

12(9-х)+12(9+х)=3(9+х)(9-х)

 216=243-3х²

3х²= 3

х=1

Ответ 1 км/ч скорость течения реки 

 

Answer 2

Calculation of River Current Speed

To determine the speed of the river current, we can use the following formula:

Speed of boat + Speed of river current = Distance / Time

Given that the speed of the boat is 9 km/h and the boat travels a distance of 12 km with the current and returns back within 3 hours, we can set up the following equation:

9 + Speed of river current = 12 / 3

Simplifying the equation, we have:

9 + Speed of river current = 4

Subtracting 9 from both sides, we find:

Speed of river current = 4 - 9 = -5 km/h

However, a negative speed for the river current does not make sense in this context. Therefore, it seems that there might be an error in the given information or calculation. Please double-check the values provided or provide additional information if available.

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