Two jets leave San Francisco at 8:00 A.M. one flying east at the speed 40km/h greater than the other, which is traveling west. At 10:00 A.M. The planes are 2480 km apart. Find their speeds

1. Make a quick sketch of the situation.
2. Work out the time that they have been flying.
3. Let v be the speed of the plane travelling west. The plane flying east as a speed of v+40 and the other plane has a speed of v. Does that make sense?
4. Find the distance traveled in terms of v for the first and second plane.
5. The sum of those two distances give 2480 km. You have one equation with one unknown. You should be able to solve this.

Can you take it from here? Can you post where you got, if not? :)