4.2.30 An airplane is preparing to land at an airport. It is 42,000 feet above the ground and is descending at the rate of 3,200 feet per minute. At the same
airport, another airplane is taking off and will ascend at the rate of 2,800 feet per minute. When will the two airplanes be at the same altitude and what will that
altitude be?

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?