Question

От пристани A к пристани B, расстояние между которыми равно 220 км, отправился с постоянной скоростью первый теплоход, а через 9 часов после этого следом за ним, со скоростью на 9 км/ч большей, отправился второй. Найдите скорость второго теплохода, если в пункт B он прибыл одновременно с первым. Ответ дайте в км/ч.

Answer 1

как-то так .. Напишите в ответе здесь

Answer 2

Problem Analysis

We are given that two boats, A and B, are traveling from port A to port B. The distance between the two ports is 220 km. The first boat travels at a constant speed, and after 9 hours, the second boat departs from port A and travels at a speed that is 9 km/h faster than the first boat. We need to find the speed of the second boat.

Solution

Let's assume the speed of the first boat is x km/h. Since the distance traveled by both boats is the same, we can set up the following equation:

Speed of first boat * Time taken by first boat = Speed of second boat * Time taken by second boat

The time taken by the first boat is the same as the time taken by the second boat, as they both arrive at port B simultaneously. Therefore, we can write:

x * 9 = (x + 9) * (9 + t)

Where t is the additional time taken by the second boat.

Simplifying the equation:

9x = (x + 9)(9 + t)

Expanding the equation:

9x = 9x + 9t + 9x + 81

Simplifying further:

9x = 18x + 9t + 81

Rearranging the terms:

9t = 81

Solving for t:

t = 81 / 9 = 9

Therefore, the additional time taken by the second boat is 9 hours.

To find the speed of the second boat, we substitute the value of t into the equation:

x * 9 = (x + 9) * (9 + 9)

Simplifying:

9x = 18x + 162

Rearranging the terms:

9x - 18x = 162

Simplifying further:

-9x = 162

Dividing both sides by -9:

x = -162 / -9 = 18

Therefore, the speed of the first boat is 18 km/h.

Since the second boat travels at a speed that is 9 km/h faster than the first boat, the speed of the second boat is:

18 + 9 = 27 km/h

Hence, the speed of the second boat is 27 km/h.

Answer

The speed of the second boat is 27 km/h.