Question

Моторная лодка прошла 46 км по течению реки за 3 часа затратив 1/9 часть этого времени на остановки.Скорость течения реки 1 3/4км/ч. Сколько километров пройдет эта лодка в стоячей воде за 2 часа?

Answer 1

1)3×1/9=1/3 часа потратила на остановки или 20 мин
2)46÷(3-1/3)=46÷2 2/3=46÷8/3=17,25 км/ч скорость по течению
3)(17,25-1 3/4)×2=(17,25-1,75)×2=15,5×2=31 км пройдет за 2 часа
Ответ: 31 км

Answer 2

Problem Analysis

To solve this problem, we need to find the distance the motorboat will travel in still water in 2 hours. We are given that the motorboat traveled 46 km in 3 hours, with 1/9 of that time spent on stops. The river's current is given as 1 3/4 km/h.

Solution

Let's break down the problem step by step:

1. Calculate the time spent on stops: - The total time taken for the journey is 3 hours. - 1/9 of this time is spent on stops. - Therefore, the time spent on stops is (1/9) * 3 = 1/3 hour.

2. Calculate the effective time spent on traveling: - The total time taken for the journey is 3 hours. - The time spent on stops is 1/3 hour. - Therefore, the effective time spent on traveling is 3 - 1/3 = 8/3 hours.

3. Calculate the speed of the motorboat in still water: - The distance traveled by the motorboat is 46 km. - The time taken for the journey is 8/3 hours. - Therefore, the speed of the motorboat in still water is 46 / (8/3) = 69/4 km/h.

4. Calculate the distance the motorboat will travel in still water in 2 hours: - The time taken for the journey in still water is 2 hours. - The speed of the motorboat in still water is 69/4 km/h. - Therefore, the distance the motorboat will travel in still water in 2 hours is (69/4) * 2 = 69/2 km.

Answer

The motorboat will travel 69/2 km in still water in 2 hours.