A rescue helicopter had to fly in a windstorm to pick up some injured hikers. The helicopter could normally fly at a speed of sixty miles per hour (60 mph). On the trip to the hikers the helicopter was flying with the wind, and on the way back it was flying against the wind. The helicopter could fly 45 miles with the wind in the same amount of time it could fly 35 miles against the wind. How fast was the wind blowing?