Question

Поезд скорость которого равна 45 к/ч,затратил на некоторый участок 4 часа. за сколько часов пройдёт этот путь поезд, если его скорость станет 40 км/ч? решить с помощью пропорции

Answer 1

Тут с помощью пропорции никак,другой результат 45*4=180(км) S 180:40=4,5(ч) Ответ:за 4,5 ч

Answer 2

Problem Analysis

We are given that a train, traveling at a speed of 45 km/h, takes 4 hours to complete a certain distance. We need to find out how long it will take for the train to cover the same distance if its speed is reduced to 40 km/h.

Solution

To solve this problem, we can set up a proportion between the speeds and the time taken. Let's denote the time taken for the train to cover the distance at 40 km/h as "x" hours.

We can set up the following proportion:

45 km/h : 40 km/h = 4 hours : x hours

To solve for "x", we can cross-multiply and solve for "x".

Calculation

Cross-multiplying the proportion, we get:

45 km/h * x hours = 40 km/h * 4 hours

Simplifying the equation:

45x = 160

Dividing both sides by 45:

x = 160 / 45

Calculating the value of "x":

x ≈ 3.56 hours

Answer

If the train's speed is reduced to 40 km/h, it will take approximately 3.56 hours to cover the same distance.