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 второго 5/6 части от первого. Через сколько часов встретятся поезда

Answer 1

90 км/ч 5/6 часть это можно понять так что 90 можно поделить на 6 по условию от туда взяли только 5 частей тем самым получили 75 км/ч спросишь как получили вообще 75 км/ч то-есть сперва делим 90 км/ч на все части которые дали то-есть 6 частей 90 км/ч после делим 90:6=15 потом умножаем на 5 частей то-есть 5 часть от 6 частей и получаем 5x15=75 км/ч

Answer 2

Problem Analysis

We are given that two trains start simultaneously from two stations that are 990 km apart and are moving towards each other. The speed of one train is 90 km/h, and the speed of the second train is 5/6 of the speed of the first train. We need to find out how many hours it will take for the trains to meet.

Solution

Let's denote the speed of the first train as v1 and the speed of the second train as v2. We are given that v1 = 90 km/h and v2 = 5/6 * v1.

To find the time it takes for the trains to meet, we can use the formula:

time = distance / relative speed

The relative speed of the two trains is the sum of their speeds because they are moving towards each other. So, the relative speed is v1 + v2.

The distance between the two stations is 990 km. Therefore, the time it takes for the trains to meet is:

time = 990 km / (v1 + v2)

Let's substitute the values of v1 and v2 into the equation and calculate the time.

v1 = 90 km/h

v2 = 5/6 * v1

v2 = 5/6 * 90 km/h

v2 = 75 km/h

time = 990 km / (90 km/h + 75 km/h)

time = 990 km / 165 km/h

time = 6 hours

Therefore, the trains will meet after 6 hours.

Answer

The trains will meet after 6 hours.

Explanation

The problem states that two trains start simultaneously from two stations that are 990 km apart and are moving towards each other. The speed of one train is 90 km/h, and the speed of the second train is 5/6 of the speed of the first train. To find the time it takes for the trains to meet, we can use the formula time = distance / relative speed. The relative speed of the two trains is the sum of their speeds because they are moving towards each other. Substituting the given values into the formula, we find that the trains will meet after 6 hours