Question

Собственная скорость теплохода 25 км/ч.расстояние между причалами 120км. если теплоход плывёт вниз по реке,то это расстояние он преодолевает за 4 ч.найдите: б)-скорость течения реки; а)-время,за которое теплоход преодолеет это расстояние вверх по реке.

Answer 1

А)  (25+x)*4=120
     100+4x=120
     4x=20
     x=5 - скорость течения

Б)  25-5=20- скорость теплохода против течения
      120/20=6-часов против течения 

Answer 2

Calculation of the Current Speed of the River

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

Current speed = Distance / Time

Given that the distance between the docks is 120 km and the time taken to cover this distance downstream is 4 hours, we can substitute these values into the formula:

Current speed = 120 km / 4 hours

Calculating this, we find that the current speed of the river is 30 km/h.

Calculation of the Time Taken to Travel Upstream

To find the time taken to travel upstream, we can use the formula:

Time = Distance / Speed

Given that the distance between the docks is 120 km and the speed of the boat is 25 km/h, we can substitute these values into the formula:

Time = 120 km / 25 km/h

Calculating this, we find that the time taken to travel upstream is 4.8 hours.

Please note that the calculations provided above are based on the information given in the question.