On a breezy day, Bonnie pedaled her human-powered aircraft 100 100 meters in 15 15 seconds going into the wind, and she made the return trip in 10 10 seconds with the wind. What were the speed of the wind and Bonnie's speed in still air? Use x x for the speed of the airplane in still air and y y for the speed of the wind
Against the wind 100 m 15 sec = 6.67 mtrs / sec With the wind 100 m 10 sec = 10 mtrs / sec psa means plane velocity in still air ws means wind speed psa -ws = 6.67 psa + ws = 10
Adding both equations we get: 2 * psa = 16.67 psa = 8.34 meters per second Since psa + ws = 10 and psa = 8.34 then wind speed = 1.66 meters per second
