Question

Теплоход прошел по течению реки 180 км за 7 часов,сделав 2 остановки по 30 минут.С какой скоростью теплоход проделает обратный путь,если скорость течения реки 3 км/ч. Решите пожалуйста:по действиям,с пояснениями и без икса(Х)!!!

Answer 1

1) 7-1=6 ч - время которое шел теплоход
2) 180/6=30 км/ч - скорость движения теплохода по течению
3) 30-3=27 км/ч - собственная скорость теплохода
4) 27-3=24 км/ч - скорость движения теплохода против течения
5) 180/24=7,5 ч - время движения теплохода против течения

Answer 2

Problem Analysis

To solve this problem, we need to find the speed at which the boat will travel on the return journey, given that it traveled 180 km downstream in 7 hours with 2 stops of 30 minutes each, and the river current is flowing at a speed of 3 km/h.

Downstream Journey

Let's first calculate the speed of the boat during the downstream journey. The boat traveled 180 km in 7 hours, including 2 stops of 30 minutes each. We need to find the speed of the boat without considering the river current.

The total time taken for the downstream journey can be calculated as follows: - Time taken for traveling 180 km at the boat's speed - Time taken for 2 stops of 30 minutes each

Let's calculate the total time taken for the downstream journey:

Time taken for traveling 180 km at the boat's speed: - Distance = 180 km - Time = 7 hours - (2 stops * 30 minutes per stop) - Speed = Distance / Time

Upstream Journey

Now, let's calculate the speed of the boat during the upstream journey. The speed of the boat during the upstream journey will be the difference between the speed of the boat in still water and the speed of the river current.

The speed of the river current is given as 3 km/h. Therefore, the speed of the boat during the upstream journey can be calculated as follows:

Speed of the boat during the upstream journey = Speed of the boat during the downstream journey - Speed of the river current

Solution

Let's calculate the speed of the boat during the downstream journey and then use that to calculate the speed of the boat during the upstream journey.

Calculation

1. Calculate the total time taken for the downstream journey: - Total time taken = 7 hours - (2 stops * 30 minutes per stop) - Total time taken = 7 hours - 1 hour - Total time taken = 6 hours

2. Calculate the speed of the boat during the downstream journey: - Distance = 180 km - Time = 6 hours - Speed = Distance / Time

3. Calculate the speed of the boat during the upstream journey: - Speed of the boat during the upstream journey = Speed of the boat during the downstream journey - Speed of the river current

Answer

The speed of the boat during the downstream journey is 30 km/h. Therefore, the speed of the boat during the upstream journey, considering a river current of 3 km/h, is 27 km/h.