Systems of equations word problem. "Flying with the wind a plane went 183 km/h. Flying into the same wind the plane only went 141 km/hr. Find the speed of the plane in still air and the speed of the wind.
Well, the plane has speed p and the wind has speed w. p+w=183, p-w=141. Add them up to get 2p=324 or p=162. The wind has speed 183-162=21 km/h, while the plane has the speed in still air 162 km/h.