Question

SOS!!!Из двух городов А и В, расстояние между которыми 390 км, навстречу друг другу одновременно выехали два автомобиля. Скорость автомобиля, выехавшего из А, равна 60 км/ч, из В - 70 км/ч. Через сколько часов после встречи автомобиль, выехавший из А прибудет в В?

Answer 1

390 : ( 60 + 70 ) = 390 : 130 = 3 ( часа ) автомобили встретятся 
390 : 60 = 6,5 ( час ) автомобиль из А приедет в В 
6,5 - 3 = 3,5 ( часа ) 
ОТВЕТ через 3,5 часа 

Answer 2

Problem Analysis

We have two cities, A and B, with a distance of 390 km between them. Two cars start simultaneously from each city towards each other. The car from city A has a speed of 60 km/h, while the car from city B has a speed of 70 km/h. We need to determine how many hours after the meeting the car from city A will arrive in city B.

Solution

To solve this problem, we can use the formula: time = distance / speed. We can calculate the time it takes for the cars to meet, and then use that time to calculate when the car from city A will arrive in city B.

Let's calculate the time it takes for the cars to meet: - The car from city A travels at a speed of 60 km/h, so the time it takes to meet is: time_A = distance / speed_A = 390 km / 60 km/h. - The car from city B travels at a speed of 70 km/h, so the time it takes to meet is: time_B = distance / speed_B = 390 km / 70 km/h.

Since both cars start simultaneously, they will meet at the same time. Therefore, the time it takes for the cars to meet is the same for both cars.

Now, let's calculate when the car from city A will arrive in city B: - The car from city A has already traveled for the time it took to meet the car from city B, so the remaining distance for the car from city A to travel is: remaining_distance = distance - (speed_A * time_A). - The car from city A will continue to travel at a speed of 60 km/h, so the time it will take to cover the remaining distance is: time_remaining = remaining_distance / speed_A.

To find the total time it takes for the car from city A to arrive in city B, we add the time it took to meet the car from city B to the time it takes to cover the remaining distance: total_time = time_A + time_remaining.

Let's calculate the values:

1. Calculate the time it takes for the cars to meet: - time_A = 390 km / 60 km/h = 6.5 hours - time_B = 390 km / 70 km/h = 5.57 hours (rounded to two decimal places)

2. Calculate the remaining distance for the car from city A to travel: - remaining_distance = 390 km - (60 km/h * 6.5 hours) = 15 km

3. Calculate the time it takes for the car from city A to cover the remaining distance: - time_remaining = 15 km / 60 km/h = 0.25 hours

4. Calculate the total time it takes for the car from city A to arrive in city B: - total_time = 6.5 hours + 0.25 hours = 6.75 hours

Therefore, the car from city A will arrive in city B after approximately 6.75 hours.

Answer

After approximately 6.75 hours after the meeting, the car that started from city A will arrive in city B.

Please let me know if there is anything else I can help you with!