Question

От пристани А к пристани В, расстояние между которыми равно 117 км, отправился с постоянной скоростью первый теплоход, а через 4 часа после этого следом за ним со скоростью, на 4 км/ч большей, отправился второй. Найдите скорость первого теплохода, если в пункт В оба теплохода прибыли одновременно.

Answer 1

5 км час он ходит незачто

Answer 2

Problem Analysis

We are given that two ships, A and B, depart from port A and port B respectively. The distance between the two ports is 117 km. The first ship travels at a constant speed, and after 4 hours, the second ship departs from port B and travels at a speed 4 km/h faster than the first ship. We need to find the speed of the first ship if both ships arrive at port B simultaneously.

Solution

Let's assume the speed of the first ship is x km/h. Since the distance between the two ports is 117 km, the first ship will take 117/x hours to travel from port A to port B.

After 4 hours, the second ship departs from port B and travels at a speed 4 km/h faster than the first ship. Therefore, the speed of the second ship is (x + 4) km/h. The second ship will take 117/(x + 4) hours to travel from port B to port A.

Since both ships arrive at port B simultaneously, the total time taken by the first ship and the second ship should be the same. Therefore, we can set up the following equation:

117/x = 117/(x + 4)

To solve this equation, we can cross-multiply:

117(x + 4) = 117x

Simplifying the equation:

117x + 468 = 117x

We can see that the variable x cancels out, which means the value of x does not affect the equation. This implies that any value of x will satisfy the equation.

Therefore, the speed of the first ship can be any positive value.

Answer

The speed of the first ship can be any positive value.