An airplane is preparing to land at an airport. It is 40,600 feet above the ground and is descending at the rate of 3,300 feet per minute. At the same airport, another airplane is taking off and will ascend at the rate of 2,500 feet per minute. When will the two airplanes be at the same altitude and what will that altitude be?
" They will be at the same altitude in ? minutes, when their altitude will be ? feet. "