1. The problem statement, all variables and given/known data A Cessna 150 averages 150 mph in still air. With a tailwind it is able to make a trip in 2 1/3 hours. Because of the headwind, it is only able to make the return trip in 3 1/2 hours. What is the average wind speed? 2. Relevant equations (1) If x = wind speed and y = still air speed ∴ resultant speed (tailwind) = x + y ∴ resultant speed (headwind) = x - y (2) d = rt 3. The attempt at a solution let x = wind speed still air speed = 150 mph tailwind time = 2 1/3 hours tailwind speed = 150 + x headwind time = 3/12 hours headwind speed = 150 - x I used these as given for the problem, expressed distance in terms of tailwind/headwind time and rates, set distance as constant (equates), solves for x then gets 57.69 as answer. but in the book, the answer is 30 mph. What is the problem with my solution? Thanks in advance.