Two airplanes are flying at the same altitude and are approaching the same airport, one flying from the North with the speed of 480 km/h,, another from the East with the speed of 400 km/h. At what rate is the distance between them decreasing when the first one is 65 km from the airport and the second plane is 48 km from the airport? Present an appropriate sketch and clear detailed solution according to Related Rates procedure for full credit