An air traffic controller spots two planes at the same altitude converging on a point as they fly at right angles to each other. One plane is 70 miles from the point moving at 420 miles per hour. The other plane is 240 miles from the point moving at 1440 miles per hour. (a) At what rate (in mi/hr) is the distance s between the planes changing? X (b) How much time (in hr) does the controller have to get one of the planes on a different flight path? x hr