text: wind speed? need help setting up equation  and coming up with answer, please? a plane flying w/ wind flew 225 mi. in 2 hrs. returning to origin, the plane flew against the wind and took 3 hrs. and 45 min. to cover the same distance. how fast was the wind blowing? easy:  the distance in both directions is exactly the same = 225 miles.  recall, also, that distance =  speed * time.  assume the plane's speed is x, wind speed is y, and that both remain constant in both directions:  with the wind, d = (x + y) * time against the wind, d = (x-y) * time  so (x + y) * 2 hours = (x - y) * 3¾ hours  2x + 2y = 225 miles  3¾x - 3¾y = 225 miles  now, you need to multiply each equation by a factor so that the y's have the same multiplier, thus:  15x + 15y = 1687.5 miles 15x -  15y = 900 miles  now, add the two equations together, thus eliminating the y value:  30x = 2587.5 miles, and thus the plane's speed, x = 86.25 miles/hour  now, substitute the value for x back into one of the equations to solve for y:  (2 * 86.25 mph) + 2y = 225  172.5 + 2y = 225  2y = 52.5 miles/hour  y = 26.25 miles per hour