Question

Два поезда движутся навстречу друг другу по параллельным путям- один со скоростью 100 км/ч, другой со скоростью 80 км/ч.Пассажир, сидящий во втром поезде, заметил, что первый поезд шёл мимо него 12с.Какова длина первого поезда

Answer 1

1) 100+80=180 км/ч скорость сближения
2) 12с=1÷300ч
3)1/300×180=0,6 км длина 1 поезда

Answer 2

Problem Analysis

We have two trains moving towards each other on parallel tracks. The first train is traveling at a speed of 100 km/h, and the second train is traveling at a speed of 80 km/h. The passenger in the second train notices that the first train passes by in 12 seconds. We need to determine the length of the first train.

Solution

To find the length of the first train, we can use the formula:

Length = Speed × Time

Let's calculate the length of the first train using this formula.

Calculation

Given: - Speed of the first train = 100 km/h - Speed of the second train = 80 km/h - Time taken for the first train to pass the passenger in the second train = 12 seconds

Using the formula Length = Speed × Time, we can calculate the length of the first train.

Length of the first train = Speed of the first train × Time taken for the first train to pass the passenger in the second train

Substituting the given values:

Length of the first train = 100 km/h × 12 seconds

Converting the speed from km/h to m/s:

Length of the first train = (100 km/h × 1000 m/km) / (60 min/h × 60 s/min) × 12 seconds

Simplifying the expression:

Length of the first train = (100 × 1000) / (60 × 60) × 12 meters

Calculating the length of the first train:

Length of the first train = 333.33 meters

Answer

The length of the first train is approximately 333.33 meters.