Question

Помогите пожалуйста с задачей по алгебре,пожааааалуйста)) ^-^ Задача: Из пункта M в пункт N выехал пассажирский поезд со скорость 70 км/ч. Через 30 минут навстречу ему из пункта N выехал скорый поезд со скоростью 90 км/ч. Расстояние МN=512 км. Через сколько часов после выезда скорый поезд встретится с пассажирским? Заранее,ОГРОМНОЕ СПАСИБО))

Answer 1

70*0.5=35км проехал пассажирский до выхода скорого
512-35=477км расстояние между ними во время выхода скорого
90+70=160км/час скорость сближения
477:160=2 157/160 часа≈3 часа

Answer 2

70x1/2=35км проехал пас.поезд за 30мин.
512-35=477км осталось между ними
т.к. они движутся навстречу, то скорости складываются
70+90=160км/ч
477/160=приблизительно 2 часа и 58 минут

Answer 3

Problem Analysis

To solve this problem, we need to find the time it takes for the express train to meet the passenger train. We are given the speeds of both trains and the distance between the two points.

Let's break down the problem: - The passenger train starts from point M and travels towards point N at a speed of 70 km/h. - After 30 minutes, the express train starts from point N and travels towards point M at a speed of 90 km/h. - The distance between points M and N is 512 km.

We need to find the time it takes for the express train to meet the passenger train.

Solution

To find the time it takes for the express train to meet the passenger train, we can use the formula:

Time = Distance / Relative Speed

The relative speed is the sum of the speeds of the two trains since they are moving towards each other.

Let's calculate the time it takes for the express train to meet the passenger train:

1. Convert the 30 minutes to hours: 30 minutes = 30/60 = 0.5 hours.

2. Calculate the relative speed: - The passenger train is moving at a speed of 70 km/h. - The express train is moving at a speed of 90 km/h. - The relative speed is 70 km/h + 90 km/h = 160 km/h.

3. Calculate the time using the formula: - Time = Distance / Relative Speed - Time = 512 km / 160 km/h - Time ≈ 3.2 hours.

Therefore, the express train will meet the passenger train approximately 3.2 hours after the express train starts from point N.

I hope this helps! Let me know if you have any further questions.