Question

Решительно задачу : два автомобиля едут навстречу друг другу. Скорость одного из них 70 км в час , а другого 80 км в час . Сейчас между ними 450 км . а) через сколько часов они встретятся ? б) если после встречи каждый продолжить движение в том же направлении, то через сколько часов после встречи расстояние между ними станет равным 300 км ?

Answer 1

70+80= 150 км/ч-общая скорость
а)450:150=3 ч
б)300:150=2 ч
        

Answer 2

А)  1)70+80=150 2)450:150=3часа- через столько встретятся 
б)  1)70+80=150км- на столько отъедут за 1 час 2) 300:150=2 часа потребуется 

Answer 3

Problem Analysis

We are given two cars traveling towards each other. The speed of one car is 70 km/h, and the speed of the other car is 80 km/h. The initial distance between them is 450 km. We need to find: a) The time it takes for the cars to meet. b) The time it takes for the distance between them to become 300 km after they meet.

Solution

a) To find the time it takes for the cars to meet, we can use the formula: time = distance / relative speed. The relative speed is the sum of the speeds of the two cars since they are traveling towards each other.

Let's calculate the time it takes for the cars to meet: - Distance: 450 km - Relative speed: 70 km/h + 80 km/h = 150 km/h

Time to meet = 450 km / 150 km/h = 3 hours. b) After the cars meet, they continue traveling in the same direction. To find the time it takes for the distance between them to become 300 km, we can use the formula: time = distance / relative speed. The relative speed is the difference between the speeds of the two cars since they are traveling in the same direction.

Let's calculate the time it takes for the distance between them to become 300 km: - Distance: 300 km - Relative speed: 80 km/h - 70 km/h = 10 km/h

Time for distance to become 300 km = 300 km / 10 km/h = 30 hours.

Answer

a) The cars will meet after 3 hours. b) After they meet, it will take 30 hours for the distance between them to become 300 km.