Question

Из пункта а в пункт б вышел поезд со скоростью 72км/ч, через 45 мин вышел второй поезд со скоростью 75км/ч. Расстояние между а и б равно 348км. На каком расстоянии от 2 поезда они встретятся.

Answer 1

45 минут=3/4 часа, за это время первый поезд прошел 54 км. Осталось проехать обоим 348-54=294 км.За 1 час оба поезда проходят 72+75=147 км. 294 км они проедут за 294:147= 2 часа.Значит 2  поезд прошел от пункта б 75х2=150 км.

Answer 2

Problem Analysis

We have two trains traveling from point A to point B. The first train has a speed of 72 km/h, and the second train has a speed of 75 km/h. The distance between points A and B is 348 km. We need to determine at what distance from the second train the two trains will meet.

Solution

To solve this problem, we can use the formula: distance = speed × time.

Let's assume that the two trains meet after time 't' hours. The first train has been traveling for 45 minutes, which is equal to 45/60 = 0.75 hours. Therefore, the first train has been traveling for a total of (0.75 + t) hours when the two trains meet.

Using the formula, we can calculate the distance traveled by each train when they meet:

- Distance traveled by the first train = speed of the first train × time traveled by the first train - Distance traveled by the second train = speed of the second train × time traveled by the second train

Since the total distance between points A and B is 348 km, the sum of the distances traveled by the two trains should be equal to 348 km:

(distance traveled by the first train) + (distance traveled by the second train) = 348 km

Let's calculate the distance traveled by each train:

Distance traveled by the first train = 72 km/h × (0.75 + t) hours Distance traveled by the second train = 75 km/h × t hours

Now we can set up the equation:

72 × (0.75 + t) + 75 × t = 348

Let's solve this equation to find the value of 't' and then calculate the distance from the second train.

Calculation

Let's solve the equation:

72 × (0.75 + t) + 75 × t = 348

Simplifying the equation:

54 + 72t + 75t = 348 147t = 294 t = 2

Now that we have the value of 't', we can calculate the distance from the second train:

Distance from the second train = speed of the second train × time traveled by the second train Distance from the second train = 75 km/h × 2 hours Distance from the second train = 150 km

Answer

The two trains will meet at a distance of 150 km from the second train.