A plane can travel 640 miles against the wind in the same town we can drive 100 miles with the wind. If the plane complot 180 mph at income air, what is the speed of the wind?
10 mph
15 mph
20 mph
d=rtw=speed of the wind640=(180-w)t800=(180+w)t640=180t-wt800=180t+wtadd1440=360tt=1440/360t=4 hourssubstitute into either equation640=(180-w)*4divide both sides by 4160=180-w160-180=-w-20=-ww=20 miles per hour which is C.
