Question

Из двух городов навстречу друг другу выехали легковая и грузовая машина.Грузовая машина ехала со скоростью 60км/ч.А легковая машина,которая выехала на 3 часа позже грузовой машины,ехала со скоростью 90км/ч.Расстояние между двумя городами-780км.сколько часов легковая машина была в пути до встречи с грузовой машиной?

Answer 1

За первых 3 часа грузовая машина проехала 180 км, значитьт растояние между машинами в момент вызда легкой машины было 780-180=600 (км), скорость приближения машин 60+90-150 (км/час), отсюда они встретились через 600/150=4 (часа)

Answer 2

Problem Analysis

We are given the following information: - A car and a truck start from two different cities towards each other. - The truck travels at a speed of 60 km/h. - The car starts 3 hours later than the truck and travels at a speed of 90 km/h. - The distance between the two cities is 780 km.

We need to determine how many hours the car was on the road before meeting the truck.

Solution

Let's assume that the car was on the road for "x" hours before meeting the truck.

The truck travels at a speed of 60 km/h, so it covers a distance of 60x km in "x" hours.

The car starts 3 hours later than the truck and travels at a speed of 90 km/h. So, it covers a distance of 90(x-3) km in "x" hours.

The total distance between the two cities is 780 km. Therefore, the sum of the distances covered by the truck and the car should be equal to 780 km.

We can write the equation as follows:

60x + 90(x-3) = 780

Simplifying the equation:

60x + 90x - 270 = 780

150x = 1050

x = 7

Therefore, the car was on the road for 7 hours before meeting the truck.

Answer

The car was on the road for 7 hours before meeting the truck.