Question

Из двух станций расстояние между которыми 990 км одновременно навстречу друг другу выехали два поезда. Скорость одного из них 90 км час а скорость другого 5 дробь 6 тых части от первого. Через сколько часов встретиться поезда

Answer 1

1)90*5/6=75(км/ч) - скорость второго поезда.
2)90+75=165(км) - скорость сближения.
3)990:165=6(ч) - время, когда поезда встретятся.
Ответ:через 6 часов.

Answer 2

Problem Analysis

To solve this problem, we need to find the time it takes for two trains, traveling towards each other, to meet. We are given the distance between the two stations (990 km) and the speeds of the two trains. One train is traveling at a speed of 90 km/h, and the other train is traveling at a speed that is 5/6 of the first train's speed.

Calculating the Time to Meet

Let's calculate the time it takes for the two trains to meet.

The formula to calculate the time it takes for two objects moving towards each other to meet is: \[ \text{Time} = \frac{\text{Distance}}{\text{Relative Speed}} \]

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

The speed of the second train is 5/6 of the speed of the first train, so the speed of the second train is \( \frac{5}{6} \times 90 \) km/h.

Solution

Using the formula above, we can calculate the time it takes for the two trains to meet.

The relative speed of the two trains is \( 90 + \frac{5}{6} \times 90 \) km/h.

The time it takes for the two trains to meet is: \[ \text{Time} = \frac{990}{90 + \frac{5}{6} \times 90} \]

Let's calculate the time.