Question

Теплоход выплыл по течению реки из Пункта А в Пункт В расстояние 165 км течение реки 4 км /ч прибыв туда делает остановку на 5 часов Всего затратил времени 18 часов Найти скорость катера в стоячей воде ?

Answer 1

18 - 5 = 13 ( час )
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13 = ( 165 / ( Х + 4)) + ( 165 /( Х - 4 )) 
13 * ( X^2 - 16) = 165 * ( X - 4) + 165 * ( X + 4 ) 
13X^2 - 208 = 165X - 660 + 165X + 660 
13X^2 - 208 = 330X 
13X^2 - 330X - 208 = 0
D = 108900 + 10816 = 119716
√ D = 346  
X1 = ( 330 + 346) : 26 = 26 ( км/час) скорость катера в стоячей воде
X2 = ( 330 - 346) : 26 = - 16/26 =  - 8/13 
Ответ 26 км/час 

Answer 2

Calculation of the Speed of the Boat in Still Water

To find the speed of the boat in still water, we need to consider the time taken for the journey and the time spent during the stoppage.

Given information: - Distance between Point A and Point B: 165 km - Speed of the river's current: 4 km/h - Time taken for the journey: 18 hours - Time spent during the stoppage: 5 hours

Let's calculate the speed of the boat in still water step by step:

1. Calculate the time taken for the journey without the stoppage: - Total time taken for the journey: 18 hours - Time spent during the stoppage: 5 hours - Time taken for the journey without the stoppage: 18 hours - 5 hours = 13 hours

2. Calculate the effective speed of the boat during the journey without the stoppage: - Distance between Point A and Point B: 165 km - Time taken for the journey without the stoppage: 13 hours - Effective speed of the boat during the journey without the stoppage: Distance / Time = 165 km / 13 hours = 12.69 km/h

3. Calculate the speed of the river's current: - Speed of the river's current: 4 km/h

4. Calculate the speed of the boat in still water using the formula: - Speed of the boat in still water = (Effective speed of the boat during the journey without the stoppage + Speed of the river's current) / 2 - Speed of the boat in still water = (12.69 km/h + 4 km/h) / 2 = 8.34 km/h

Therefore, the speed of the boat in still water is 8.34 km/h.

Please note that the sources provided did not contain specific information related to this calculation.