Question

Расстояние от пункта А до пункта Б моторная лодка плыла по течению реки 1,3 ч,а от пункта а от пункта Б до пункта А-1,9ч.Скорость течения реки 2,4 км/ч.Найдите собственную скорость моторной лодки.

Answer 1

х - собственная скорость лодки

х+2,4 - скорость по течению реки

х-2,4 - скорость против течения реки

 

1,3*(х+2,4)=1,9*(х-2,4)

1,3х+3,12=1,9х-4,56

1,9х-1,3х=3,12+4,56

0,6х=7,68

х=12,8 км/ч - скорость лодки

 

 

Answer 2

Calculation of the Boat's Speed

To find the speed of the motorboat, we need to calculate the distance between points A and B and the time it takes for the boat to travel that distance. We are given that the boat traveled from point A to point B with the current in 1.3 hours and from point B to point A against the current in 1.9 hours. The speed of the river current is given as 2.4 km/h.

Let's denote the speed of the motorboat as Vb and the distance between points A and B as D. We can set up the following equations:

1. When the boat is traveling with the current: - Time = Distance / (Boat's speed + Current's speed) - 1.3 hours = D / (Vb + 2.4 km/h)

2. When the boat is traveling against the current: - Time = Distance / (Boat's speed - Current's speed) - 1.9 hours = D / (Vb - 2.4 km/h)

To solve these equations, we can use the method of substitution or elimination. Let's use the method of substitution:

From equation 1, we can express D in terms of Vb: D = 1.3 hours * (Vb + 2.4 km/h)

Substituting this value of D into equation 2: 1.9 hours = (1.3 hours * (Vb + 2.4 km/h)) / (Vb - 2.4 km/h)

Now, we can solve this equation to find the value of Vb, which represents the speed of the motorboat.

Let's calculate the value of Vb using the given information.