Question

От двух пристаней расстояние между которыми по реке равно 144 км одновременно навстречу друг другу вышли две яхты. скорость яхты стоячий в воде 36 км в час.через сколько часов встретятся эти яхты, если скорость течения реки 2 км в час

Answer 1

36+2=38 км/ч скорость яхты по течению
36-2=34 км/ч скорость яхты против течения
38+34=72 км/ч скорость сближения яхт
144:72=2 ч 
Отв: через 2 часа они встретятся

Answer 2

36-2=34 км/ч скорость первой яхты (медленные какие-то яхты))) 
36+2=38 км/ч скорость второй яхты
34+38=72 км/ч - скорость двух яхт (уже что-то ))))
144/72=2 ч они встретятся через 2 часа

Answer 3

Problem Analysis

We are given that the distance between two piers along a river is 144 km. Two yachts start simultaneously from each pier and are moving towards each other. The speed of the yachts in still water is 36 km/h, and the speed of the river current is 2 km/h. We need to determine how many hours it will take for the yachts to meet.

Solution

To solve this problem, we can use the concept of relative velocity. The relative velocity of the yachts is the sum of their individual velocities. Let's denote the speed of the first yacht as `v1` and the speed of the second yacht as `v2`. Since the yachts are moving towards each other, their relative velocity is the sum of their speeds: `v_rel = v1 + v2`.

In this case, the speed of the yachts in still water is given as 36 km/h. Since the yachts are moving against the current, the effective speed of each yacht will be reduced by the speed of the river current. Therefore, the effective speed of each yacht can be calculated as `v_effective = v_in_still_water - v_current`.

Let's substitute the given values into the equation to find the effective speed of each yacht: - For the first yacht: `v1_effective = 36 - 2 = 34 km/h` - For the second yacht: `v2_effective = 36 - 2 = 34 km/h`

Now we can calculate the time it will take for the yachts to meet by dividing the distance between the piers by their relative velocity: `time = distance / relative_velocity`

Substituting the given values into the equation: `time = 144 / (v1_effective + v2_effective)`

Let's calculate the time it will take for the yachts to meet.

Calculation

Substituting the values into the equation: `time = 144 / (34 + 34)`

Calculating the sum in the denominator: `time = 144 / 68`

Calculating the time: `time = 2.1176 hours`

Answer

The two yachts will meet approximately after 2.12 hours.

Explanation

The two yachts will meet after approximately 2.12 hours. This calculation is based on the given information that the distance between the piers is 144 km, the speed of the yachts in still water is 36 km/h, and the speed of the river current is 2 km/h. By considering the relative velocity of the yachts and dividing the distance by their relative velocity, we find that it will take approximately 2.12 hours for the yachts to meet.