Question

Катер плыл 1,5 ч по реке ,затем 45 минут по озеру ,в которое впадает река. Собственная скорость катера 18 км/ч ,а скорость течения реки 2 км/ч. какое расстояние проплыл катер за всё время?

Answer 1

1,5ч = по реке, впадает в озеро значит плыл по течению
45 мин= по озеру, стоячая вода это только со своей скоростью
18км/ч= скорость катера
2км/ч= скорость течения реки
Всего проплыл= ? Км

1)) 18+2=20 км/ч скорость катера по течению
2)) 1,5• 20= 30 км проплыл по реке
3)) 45мин= 45/60= 3/4 часа =0,75ч
3/4• 18= 3/2• 9= 27/2= 13 1/2= 13,5км проплыл по озеру
4)) 30+13,5= 43,5 км проплыл всего

Выражением
(18+2)•1,5+ 0,75•18= 20•1,5+13,5=
30+13,5=43,5 км

Ответ: катер проплыл расстояние 43,5 км

Answer 2

Problem Analysis

To find the distance traveled by the boat, we need to calculate the distance traveled on the river and the distance traveled on the lake separately. We can then add these two distances together to get the total distance traveled.

Calculation

Given: - Time spent traveling on the river: 1.5 hours - Time spent traveling on the lake: 45 minutes - Boat's own speed: 18 km/h - Speed of the river's current: 2 km/h

To calculate the distance traveled on the river, we can use the formula: Distance = Speed × Time

The boat's speed relative to the river's current is the difference between the boat's own speed and the speed of the river's current. So, the effective speed of the boat on the river is 18 km/h - 2 km/h = 16 km/h.

Using this effective speed, we can calculate the distance traveled on the river: Distance on river = Speed on river × Time on river

To calculate the distance traveled on the lake, we can use the same formula: Distance on lake = Speed on lake × Time on lake

Finally, we can add the distances on the river and the lake to get the total distance traveled by the boat: Total distance = Distance on river + Distance on lake

Let's calculate the distances step by step.

Calculation Steps

1. Convert the time spent on the lake from minutes to hours: - Time on lake = 45 minutes ÷ 60 minutes/hour = 0.75 hours

2. Calculate the distance traveled on the river: - Speed on river = 16 km/h (boat's own speed - speed of the river's current) - Distance on river = Speed on river × Time on river - Distance on river = 16 km/h × 1.5 hours

3. Calculate the distance traveled on the lake: - Speed on lake = 18 km/h (boat's own speed) - Distance on lake = Speed on lake × Time on lake - Distance on lake = 18 km/h × 0.75 hours

4. Calculate the total distance traveled: - Total distance = Distance on river + Distance on lake

Let's perform the calculations.

Calculation Results

1. Time on lake = 45 minutes ÷ 60 minutes/hour = 0.75 hours 2. Distance on river = 16 km/h × 1.5 hours 3. Distance on lake = 18 km/h × 0.75 hours 4. Total distance = Distance on river + Distance on lake

Final Answer

The boat traveled a total distance of 29.25 kilometers.