Math (URGENT)
posted by John on .
A word problem.
David flew 300km on a commuter plane, then 2000km on a passenger jet. The passenger jet flew twice as fast as the commuter plane. The total flying time for the journey was 3.25 hours. What was the speed of each plane, in kilometers per hour?
Please help. I've been trying to tackle this problem for an hour+ and had no luck solving it.

let the speed of the commuter plane be x km/h
then the speed of the passenger jet is 2x km/h
300/x + 2000/2x = 3.25
300/x + 1000/x = 3.25
1300/x = 3.25
3.25x = 1300
x = 1300/3.25 = 400
so ......