If a plane flies 300 miles in 2 hours with the wind and 300 miles in 6 hours against the wind, what is the speed of the wind?
Correct: C
Let's denote the speed of the plane in still air as P and the speed of the wind as W. When flying with the wind, the effective speed is P + W, and against the wind, it's P - W. The time to travel 300 miles with the wind is 2 hours, so the speed with the wind is 300 / 2 = 150 mph. The time against the wind is 6 hours, so the speed against the wind is 300 / 6 = 50 mph. Now, we have two equations: P + W = 150 and P - W = 50. Adding these two equations eliminates W and gives us 2P = 200, so P = 100 mph. Substituting P = 100 into P + W = 150 gives us 100 + W = 150, which means W = 50 mph.