Question

Катер у стоячій воді має швидкість 18 км за год. швидкість течії 2км за год. знайдіть відстань між 2 пристанями,якщо рейс туди і назад катер пройшов за 9 год . ДОПОМОЖІТЬ БУДЬ ЛАСКА РІВНЯННЯМ!!!!​

Answer 1

Розв'язання:

Нехай відстань між двома пристанями х км,

тоді катер за течією річки йшов х/(18+2) годин, а проти течії - х/(18-2) годин. Оскільки рейс туди і назад катер пройшов за 9 годин, то можна скласти рівняння:

$\frac{x}{18 + 2} + \frac{x}{18 - 2} = 9$

$\frac{x}{20} + \frac{x}{16} = 9$

$\frac{16x + 20x}{20 \times 16} = 9$

$\frac{36x}{320} = 9 \: \: \: \: | \times \frac{1}{9}$

$\frac{4x}{320} = 1$

$4x = 320$

$x = \frac{320}{4}$

$x = 80$

Отже, відстань між двома пристанями 80 км.

Відповідь: 80 км.

Answer 2

To find the distance between the two piers, we can use the formula:

Distance = Speed × Time

Let's break down the information given in the problem:

- The speed of the boat in still water is 18 km/h. - The speed of the current is 2 km/h. - The boat took a total of 9 hours for the round trip.

Now, let's solve the problem step by step:

Step 1: Calculate the time for one leg of the trip

Since the boat took a total of 9 hours for the round trip, the time for one leg of the trip is half of that, which is 4.5 hours.

Step 2: Calculate the effective speed of the boat

To calculate the effective speed of the boat, we need to consider the speed of the boat in still water and the speed of the current. When the boat is moving against the current, its effective speed will be reduced, and when it is moving with the current, its effective speed will be increased.

Let's denote the speed of the boat in still water as B and the speed of the current as C.

When the boat is moving against the current, its effective speed is B - C. When the boat is moving with the current, its effective speed is B + C.

In this case, the boat is traveling both ways, so we need to consider both scenarios.

Step 3: Calculate the distance

To calculate the distance, we can use the formula:

Distance = Speed × Time

For the first leg of the trip (against the current), the effective speed of the boat is B - C and the time is 4.5 hours. So the distance covered in this leg is:

Distance1 = (B - C) × 4.5

For the second leg of the trip (with the current), the effective speed of the boat is B + C and the time is 4.5 hours. So the distance covered in this leg is:

Distance2 = (B + C) × 4.5

Since the total distance covered is the sum of the distances for both legs, we can write:

Total Distance = Distance1 + Distance2

Now, let's substitute the values given in the problem and solve for the total distance:

Total Distance = (B - C) × 4.5 + (B + C) × 4.5

Step 4: Solve the equation

To solve the equation, we need to know the values of B and C. Unfortunately, the problem does not provide these values. Without the specific values for the speed of the boat in still water and the speed of the current, we cannot calculate the total distance.

Please provide the specific values for B and C, and I will be happy to help you solve the equation and find the distance between the two piers.