Question

От двух пристаней отошли одновременно навстречу друг другу катер и лодка. Они встретились через 4 ч. Скорость лодки 20 км в час , а скорость катера в 3 раза больше. Чему равно расстояние между пристанями ?

Answer 1

1)20x3=60(км/ч)-скорость катера.
2)20+60=80(км/ч)-скорость сближения.
3)4x80=320(км)-расстояние между пристанями.
Ответ: расстояние между пристанями 320 км.

Answer 2

Problem Analysis

To solve this problem, we need to find the distance between the two piers. We know that a boat and a motorboat set off from two piers at the same time and meet after 4 hours. The speed of the boat is 20 km/h, and the speed of the motorboat is 3 times greater.

Calculating the Distance

Let's denote the speed of the boat as v km/h and the speed of the motorboat as 3v km/h. The total distance covered by both the boat and the motorboat is the same, and it is equal to the distance between the piers.

The formula to calculate the distance is: Distance = Speed × Time

For the boat: Distance = 20 km/h × 4 h = 80 km

For the motorboat: Distance = (3v) km/h × 4 h = 12v km

Since both distances are the same, we can equate them: 80 km = 12v km

Solving for the Distance

Let's solve for v to find the speed of the boat and then calculate the distance between the piers.

12v = 80 v = 80 / 12 v = 6.67 km/h

Now that we have the speed of the boat, we can calculate the distance between the piers: Distance = 20 km/h × 4 h = 80 km

Answer

The distance between the piers is 80 kilometers.