posted by winterWX .
After flying for 15 min in a wind blowing 42 km/h at an angle of 30° south of east, an airplane pilot is over a town that is 50 km due north of the starting point. What is the speed of the airplane relative to the air?
This is a vector equation. I would do it graphically. vector from start to end, minus the wind vector, is equal to speed of airplane.