Question

Из пункта А в пункт В выехал автобус, а через 2 часа вслед за ним выехал легковой автомобиль, скорость которого была на 80 км/ч больше скорости автобуса. Чему была равна скорость автомобиля если он прибыл в пункт В на 40 мин раньше автобуса, а вся дорога от А до В заняла у него 1 час 20 мин?

Answer 1

x/90x/90=x/60-2/32x=3x-120x=120 

Answer 2

Problem Analysis

We are given that a bus left point A and after 2 hours, a car with a speed 80 km/h faster than the bus left as well. The car arrived at point B 40 minutes earlier than the bus, and the total travel time from A to B for the car was 1 hour and 20 minutes. We need to find the speed of the car.

Solution

Let's assume the speed of the bus is x km/h. Since the car is 80 km/h faster than the bus, the speed of the car is x + 80 km/h.

We know that the car arrived at point B 40 minutes earlier than the bus. This means that the car took 40 minutes less time to travel from A to B compared to the bus. Since the total travel time for the car was 1 hour and 20 minutes, we can convert this to minutes: 1 hour = 60 minutes, so 1 hour and 20 minutes is equal to 80 minutes.

Now, let's calculate the time it took for the bus to travel from A to B. Since the car arrived 40 minutes earlier, the bus took 80 minutes + 40 minutes = 120 minutes to travel from A to B.

We can use the formula time = distance / speed to calculate the distance traveled by the bus and the car.

The distance traveled by the bus is equal to the speed of the bus multiplied by the time taken by the bus: distance_bus = x * 120.

The distance traveled by the car is equal to the speed of the car multiplied by the time taken by the car: distance_car = (x + 80) * 80.

Since the distance from A to B is the same for both the bus and the car, we can equate the two distances and solve for x:

x * 120 = (x + 80) * 80

Let's solve this equation to find the value of x.