Question

4) два автомобиля одновременно отъехали от зданий, расстояние между которыми 4,5 км, по прямолинейным дорогам, пересекающимися род прямым углом; и одновременно подъехали к их пересечению. Скорость одного автомобиля 60 км/ч, другого-80 км/ч. Сколько примерно времени прошло с момента выезда автомобилей до момента их встречи?

Answer 1

(60 х) ^2 + (80x)^2 = 4.5^2
3600x^2 + 6400x^2 = 20.25
x^2 = 0.002025
х = 0,045 часа
0,045 часа = 2,7 минуты = 2 мин 42 сек
 вроде бы правильный ответ А 2 мин 30 сек

Answer 2

Problem Analysis

We have two cars that simultaneously start from two buildings, with a distance of 4.5 km between them. The cars travel along straight roads that intersect at a right angle. The speed of one car is 60 km/h, and the speed of the other car is 80 km/h. We need to determine approximately how much time has passed from the moment the cars started until they meet at the intersection.

Solution

To solve this problem, we can use the formula: time = distance / speed. We will calculate the time it takes for each car to reach the intersection, and then take the maximum of these two times as the answer.

Let's calculate the time it takes for the first car to reach the intersection: - Distance traveled by the first car = 4.5 km - Speed of the first car = 60 km/h - Time taken by the first car = distance / speed = 4.5 km / 60 km/h

Now let's calculate the time it takes for the second car to reach the intersection: - Distance traveled by the second car = 4.5 km - Speed of the second car = 80 km/h - Time taken by the second car = distance / speed = 4.5 km / 80 km/h

Finally, we take the maximum of these two times to find the approximate time it takes for the cars to meet at the intersection.

Calculation

Let's calculate the time taken by each car to reach the intersection:

Time taken by the first car: - Distance = 4.5 km - Speed = 60 km/h - Time = distance / speed = 4.5 km / 60 km/h = 0.075 hours

Time taken by the second car: - Distance = 4.5 km - Speed = 80 km/h - Time = distance / speed = 4.5 km / 80 km/h = 0.05625 hours

Taking the maximum of these two times: - Maximum time = max(0.075 hours, 0.05625 hours) = 0.075 hours

Answer

Approximately 0.075 hours have passed from the moment the cars started until they meet at the intersection.

Please note that this is an approximate calculation and does not take into account factors such as acceleration, deceleration, or any delays that may occur during the journey.