Question

Расстояние между двумя пунктами катер прошол по течению реки за 4 ч а против течения за 5 ч за сколькоже пунктами проплывёт плот

Answer 1

Пусть х км/ч скорость катера, а укм/ч скорость течения реки( скорость плота). Тогда скорость катера по течению реки (х + у) км/ч. а против течения реки (х - у) км/ч. Весь путь возьмем за единицу. Нам известно, что это расстояние катер проплывает по течению за 4 часа, а против течения за 5 часов. Составляем систему уравнений: система 1 / ( х + у) = 4 и 1 / ( х - у) = 5; система: х + у = 1/4, х - у = 1/5 из второго уравнения системы выразим х и подставим в первое уравнение и получим систему: х = 1/5 + у, 1/5 + у + у= 1/4; умножим второе уравнение системы на 20 и получим систему: х = 1/5 + у, 4 + 40у = 5; система х = 1/5 + у, 40у = 1; система х = 1/5 + у, у = 1/40 км/ч. Найдем время за которое проплывет плот это расстояние. 1 : 1/40 = 40 (ч.) Ответ: за 40 часов.

Answer 2

Calculation of Distance Traveled by the Boat

To calculate the distance traveled by the boat, we need to determine the speed of the boat and the time it took to travel in each direction.

Let's assume that the speed of the boat is constant and denoted by v.

According to the given information, the boat traveled downstream (with the current) for 4 hours and upstream (against the current) for 5 hours.

The distance traveled downstream can be calculated using the formula: distance = speed × time.

Therefore, the distance traveled downstream is 4v.

Similarly, the distance traveled upstream is 5v.

To find the total distance traveled by the boat, we can add the distances traveled downstream and upstream: total distance = distance downstream + distance upstream.

Substituting the values, we get: total distance = 4v + 5v = 9v.

Therefore, the boat will travel 9v units of distance in total.

Calculation of Distance Traveled by the Raft

To calculate the distance traveled by the raft, we need to consider the relative speed of the raft with respect to the river current.

Let's assume that the speed of the river current is constant and denoted by c.

When the raft is moving downstream (with the current), the effective speed of the raft is the sum of its own speed and the speed of the current. Therefore, the effective speed is v + c.

Similarly, when the raft is moving upstream (against the current), the effective speed is the difference between its own speed and the speed of the current. Therefore, the effective speed is v - c.

To calculate the distance traveled by the raft, we can use the formula: distance = speed × time.

For the downstream journey, the distance traveled by the raft is (v + c) × 4.

For the upstream journey, the distance traveled by the raft is (v - c) × 5.

To find the total distance traveled by the raft, we can add the distances traveled downstream and upstream: total distance = distance downstream + distance upstream.

Substituting the values, we get: total distance = (v + c) × 4 + (v - c) × 5.

Simplifying the expression, we get: total distance = 9v + c.

Therefore, the raft will travel 9v + c units of distance in total.

Please note that the exact numerical values for the speed of the boat, speed of the current, and the total distance traveled cannot be determined without additional information. The above calculations provide a general formula for calculating the distances based on the given information.