Question

помогите. пожалуйста решить задачу! Из двух лодочных станций. расположенных на реке, одновременно навстречу друг другу вышли две моторные лодки с одинаковой собственной скоростью. Началась гроза, и одна из лодок вернулась на станцию, пройдя по течению 20 мин, а другая повернула обратно через 30 мин после выхода со станции. Обратный путь обеих лодок в сумме занял 50 мин. Во сколько раз скорость лодки по течению реки больше скорости лодки против течения реки?

Answer 1

 х скорость велосипедиста 
x+50 скорость мотоциклиста 


60/x-60/(x+50)=5 
(60x+3000-60x)/(x^2+50x)=5 
3000/(x^2+50x)=5 
x^2+50x-600=0 
D=2500+2400=4900=70^2 
x1=(-50+70)/2=10 
x2=(-50-70)/2=-60 
ответ получается 10 км.ч.

Я НЕ ЗНАЮ ТАК ИЛИ НЕТ.НУ МЫ РЕШАЛИ ТАК.

Answer 2

Problem Analysis

We have two motorboats that start simultaneously from two boat stations on a river. Both boats have the same speed. However, due to a storm, one boat returns to the station after 20 minutes, while the other boat turns back after 30 minutes. The total time for the round trip of both boats is 50 minutes. We need to determine the ratio of the speed of the boat with the current to the speed of the boat against the current.

Solution

Let's assume the speed of each boat is x units per minute. We need to find the ratio of the speed of the boat with the current to the speed of the boat against the current.

To solve this problem, we can use the concept of relative speed. The relative speed of the boat with the current is the sum of the boat's speed and the speed of the current, while the relative speed of the boat against the current is the difference between the boat's speed and the speed of the current.

Let's calculate the time taken by each boat for the round trip.

The boat that returns to the station after 20 minutes: - Time taken to go downstream (with the current): 20 minutes - Time taken to go upstream (against the current): 30 minutes - Total time for the round trip: 20 + 30 = 50 minutes

The boat that turns back after 30 minutes: - Time taken to go downstream (with the current): 30 minutes - Time taken to go upstream (against the current): 20 minutes - Total time for the round trip: 30 + 20 = 50 minutes

Since the total time for the round trip is the same for both boats, we can set up the following equation:

Time taken downstream by boat 1 + Time taken upstream by boat 1 = Time taken downstream by boat 2 + Time taken upstream by boat 2

Let's substitute the values:

20 + 30 = 30 + 20

This equation is true, which means the boats have the same speed.

Therefore, the ratio of the speed of the boat with the current to the speed of the boat against the current is 1:1.

Answer

The ratio of the speed of the boat with the current to the speed of the boat against the current is 1:1.