Question

Лодка шла по течению со скоростью 12,6км/ч,а против течения - со скоростью 8,8 км/ч.Найдите скорость течения,зная,что собственная скорость лодки не изменялась.Плииииз.Решите срочно !

Answer 1

Если лодка плывет против течения,то мы к её скорости прибавляем скорость реки,если же плывем по течению,то от скорости лодки отнимаем скорость реки.Здесь будем решать системой,возьмем скорость лодки за-х,а скорость течения за-у.{x+y=12,6 и x-y=8,8 Теперь воспользуемся правилом сложения (сложим х с х,у с у и число с числом).Получим 2ч=21,4 (у самоуничтожается). Находим х=21,4:2=10,7.Теперь подставим полученный х в любое из уравнений,например 10,7+у=12,6.Отсюда находим у=12,6-10,7=1,9.Ответ:скорость течения=1,9

Answer 2

Problem Analysis

To find the speed of the current, we can set up a system of equations based on the information given. Let's assume the speed of the current is represented by c and the speed of the boat in still water is represented by b.

Given: - Speed of the boat downstream (with the current): 12.6 km/h - Speed of the boat upstream (against the current): 8.8 km/h

We can set up the following equations: 1. b + c = 12.6 (equation for the boat's speed downstream) 2. b - c = 8.8 (equation for the boat's speed upstream)

By solving this system of equations, we can find the value of c, which represents the speed of the current.

Solution

To solve the system of equations, we can use the method of elimination. By adding the two equations together, we can eliminate the variable b and solve for c:

(b + c) + (b - c) = 12.6 + 8.8

Simplifying the equation:

2b = 21.4

Dividing both sides of the equation by 2:

b = 10.7

Now that we have the value of b, we can substitute it back into one of the original equations to solve for c:

10.7 + c = 12.6

Subtracting 10.7 from both sides of the equation:

c = 12.6 - 10.7

Simplifying the equation:

c = 1.9

Therefore, the speed of the current is 1.9 km/h.

Answer

The speed of the current is 1.9 km/h.