Two airplanes leave an airport at the same time, flying in the same direction. One plane is flying at twice the speed of the other. If after 4 hours they are 1800 km apart, find the speed of each plane.

One plane has a speed of 450 km/h and the other has a speed of 900 km/h.

Step-by-step explanation:

I am going to say that:

The speed of the first plane is x.

The speed of the second plane is y.

One plane is flying at twice the speed of the other.

I will say that y = 2x. We could also say that x = 2y.

Two airplanes leave an airport at the same time, flying in the same direction

They fly in the same direction, so their relative speed (difference) at the end of each hour is y - x = 2x - x = x.

If after 4 hours they are 1800 km apart, find the speed of each plane

After 1 hour, they will be x km apart. After 4, 1800. So

1 hour - x km apart

4 hours - 1800 km apart

4x = 1800

x = 1800/4

x = 450

2x = 2*450 = 900

One plane has a speed of 450 km/h and the other has a speed of 900 km/h.