Question

В полдень от пристани отошел теплоход со скоростью 16км/ч. Через 3ч вслед ему отошел другой теплоход и через 12/ч догнал первый. с какой скоростью двигался второй теплоход? Помогите плииз, спасибо

Answer 1

Второй теплоход догонит первый через 
1).3 + 12 = 15 ч 
За это время первый теплоход пройдет расстояние 
2).15 • 16 = 240 км 
Скорость второго теплохода составит 
3).240 : 12 = 20 км/ч                            Ответ:20км/ч

Answer 2

Problem Analysis

We are given that a steamboat departs from a pier at noon with a speed of 16 km/h. Another steamboat departs after 3 hours and catches up with the first steamboat in 12 hours. We need to determine the speed of the second steamboat.

Solution

Let's assume the speed of the second steamboat is x km/h.

The first steamboat travels for 3 hours before the second steamboat starts. Therefore, the distance covered by the first steamboat in these 3 hours is:

Distance1 = Speed1 * Time1 = 16 km/h * 3 h = 48 km.

Now, let's consider the time it takes for the second steamboat to catch up with the first steamboat. Since both steamboats are traveling in the same direction, the relative speed between them is the difference in their speeds:

Relative Speed = Speed2 - Speed1 = x km/h - 16 km/h = (x - 16) km/h.

The second steamboat catches up with the first steamboat in 12 hours. Therefore, the distance covered by the second steamboat in these 12 hours is:

Distance2 = Relative Speed * Time2 = (x - 16) km/h * 12 h = 12x - 192 km.

Since the second steamboat catches up with the first steamboat, the distances covered by both steamboats must be equal:

Distance1 = Distance2.

Substituting the values of Distance1 and Distance2, we get:

48 km = 12x - 192 km.

Simplifying the equation, we have:

12x = 240 km.

Dividing both sides of the equation by 12, we find:

x = 20 km/h.

Therefore, the speed of the second steamboat is 20 km/h.

Answer

The second steamboat was moving at a speed of 20 km/h.