Question

Из города в противоположных направлениях выехали 2 автомобиля.Когда один из них проехал 420км со скоростью 70км/ч то расстояние между ними стало равным 780км. Какова скорость второго автомобиля. Решите пж .Срочно.

Answer 1

Находим t 1=420:70=6 потом 780-420=360 это сколько км проехал второй 
360 км:6 ч=60
ответ 60 км\ч

Answer 2

1)420÷70=6(часов) - ехал первый
2)780-420=360(км) - проехал второй
3)360÷6=60(км/ч)
Ответ: второй автомобиль ехал со скоростью 60 км/ч.

Answer 3

Problem Analysis

We have two cars that start from the same city and travel in opposite directions. When one of the cars has traveled 420 km at a speed of 70 km/h, the distance between the two cars becomes 780 km. We need to find the speed of the second car.

Solution

Let's assume the speed of the second car is x km/h.

The first car has traveled 420 km at a speed of 70 km/h. Therefore, the time taken by the first car is: time taken by the first car = distance / speed = 420 km / 70 km/h = 6 hours.

During this time, the second car has also traveled for 6 hours at a speed of x km/h. Therefore, the distance traveled by the second car is: distance traveled by the second car = speed * time = x km/h * 6 hours = 6x km.

The total distance between the two cars is 780 km. So, we can write the equation: distance traveled by the first car + distance traveled by the second car = total distance 420 km + 6x km = 780 km

Now, let's solve this equation to find the value of x.

Calculation

420 km + 6x km = 780 km

Subtracting 420 km from both sides: 6x km = 780 km - 420 km 6x km = 360 km

Dividing both sides by 6: x km = 360 km / 6 x km = 60 km/h

Answer

Therefore, the speed of the second car is 60 km/h.

Please let me know if you need any further assistance.