A Delta 727 traveled 560 mph with the wind and 480 mph again

A Delta 727 traveled 560 mph with the wind and 480 mph against the wind. Find the speed of the plane in still air and the speed of the wind

Solution

a = airspeed of plane
w = wind speed
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a+w = 560
a-w = 480
---------- Add
2a = 1040
a = 520 mph
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w = 40 mph