Question

Скорость течения реки - 2 км/ч, а собственная скорость катера - 15 км/ч. время, которое потребуется катеру на путь 68 км при движении по течению реки. время, которое потребуется катеру на путь 78 км при движении против течения реки.

Answer 1

При движении по течению реки скорости складываются
68:(15+2)=68:17=4 ч
при движении против течения скорость вычиается
78:(15-2)=78:13=6 ч

Answer 2

68/(15+2)=4
78/(15-2)=6

Answer 3

Calculation of Time for the Boat to Travel 68 km with the Current

To calculate the time it will take for the boat to travel 68 km with the current, we need to consider the speed of the current and the speed of the boat.

Given: - Speed of the current: 2 km/h - Speed of the boat: 15 km/h

To calculate the effective speed of the boat when moving with the current, we add the speed of the boat and the speed of the current: Effective speed = Speed of the boat + Speed of the current = 15 km/h + 2 km/h = 17 km/h

Now, we can calculate the time it will take for the boat to travel 68 km with the current using the formula: Time = Distance / Speed

Substituting the values: Time = 68 km / 17 km/h = 4 hours

Therefore, it will take the boat 4 hours to travel 68 km with the current.

Calculation of Time for the Boat to Travel 78 km against the Current

To calculate the time it will take for the boat to travel 78 km against the current, we need to consider the speed of the current and the speed of the boat.

Given: - Speed of the current: 2 km/h - Speed of the boat: 15 km/h

To calculate the effective speed of the boat when moving against the current, we subtract the speed of the current from the speed of the boat: Effective speed = Speed of the boat - Speed of the current = 15 km/h - 2 km/h = 13 km/h

Now, we can calculate the time it will take for the boat to travel 78 km against the current using the formula: Time = Distance / Speed

Substituting the values: Time = 78 km / 13 km/h = 6 hours

Therefore, it will take the boat 6 hours to travel 78 km against the current.

Note: The calculations assume a constant speed throughout the journey and do not take into account other factors such as changes in the current or variations in the boat's speed.