Question

Из двух городов, расстояние между которыми равно 390 км, навстречу друг другу одновременно выехали два автомобиля. Найдите скорость первого автомобиля,если скорость второго равна 60 км/ч и автомобили встретились через 3 часа после выезда. Ответ дайте в км/ч.

Answer 1

390-(60*3)=210

210/30=70км/ч

 

Answer 2

Problem Analysis

We are given that two cars start simultaneously from two cities that are 390 km apart and are moving towards each other. We are also given that the second car is traveling at a speed of 60 km/h and they meet after 3 hours. We need to find the speed of the first car.

Solution

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

To find the speed of the first car, we can use the formula:

Distance = Speed × Time

The distance covered by the first car in 3 hours is 3x km, and the distance covered by the second car in 3 hours is 60 × 3 = 180 km.

Since the two cars are moving towards each other, the sum of the distances covered by both cars should be equal to the total distance between the two cities, which is 390 km.

So, we can write the equation:

3x + 180 = 390

Simplifying the equation:

3x = 390 - 180

3x = 210

Dividing both sides of the equation by 3:

x = 70

Therefore, the speed of the first car is 70 km/h.