Question

ПОЖАЛУЙСТА ПОМОГИТЕ! Расстояние между двумя поселками равно 46,2 км. Из этих поселков навстречу друг другу движутся две моторные лодки. Лодка идущая по течению, собственная скорость которой 18 км/ч, до встречи шла 1 час 12 мин.; другая лодкасобственная скорость которой 17 км/ч, шла до встречи 1,5 часа. Найдите скорость течения реки

Answer 1

X - скорость течения
18+x - скорость лодки по течению
17-x - скорость лодки против течения
1 час 12 мин =1,2 часа
1,2*(18+x)+1,5*(17-x)=46,2
21,6+1,2x+25,5-1,5x=46,2
0,3x=0,9
x=3

Answer 2

Problem Analysis

We are given that the distance between two settlements is 46.2 km. Two motorboats are moving towards each other from these settlements. The first boat, moving with the current, took 1 hour and 12 minutes to meet, while the second boat, moving against the current, took 1.5 hours to meet. We need to find the speed of the river's current.

Solution

Let's assume the speed of the river's current is x km/h.

The speed of the first boat relative to the river's current is the sum of its own speed and the speed of the current, which is 18 + x km/h. The speed of the second boat relative to the river's current is the difference between its own speed and the speed of the current, which is 17 - x km/h.

We can use the formula distance = speed × time to calculate the distances traveled by each boat.

For the first boat: - Distance = (18 + x) km/h × 1.2 hours (1 hour 12 minutes) - Distance = (18 + x) × 1.2 km

For the second boat: - Distance = (17 - x) km/h × 1.5 hours - Distance = (17 - x) × 1.5 km

Since the total distance between the two settlements is 46.2 km, the sum of the distances traveled by the two boats should be equal to 46.2 km.

Therefore, we can write the equation: (18 + x) × 1.2 + (17 - x) × 1.5 = 46.2

Now, let's solve this equation to find the value of x.

Calculation

(18 + x) × 1.2 + (17 - x) × 1.5 = 46.2

Simplifying the equation: 21.6 + 1.2x + 25.5 - 1.5x = 46.2

Combining like terms: 47.1 - 0.3x = 46.2

Subtracting 47.1 from both sides: -0.3x = -0.9

Dividing both sides by -0.3: x = 3

Answer

The speed of the river's current is 3 km/h.

Please let me know if I can help you with anything else.