Question 411180


Let "{{{v}}}" be speed of plane in still air.
Let "{{{v1}}}" be speed of the wind.

Equations:

{{{v + v1 = 480 mph}}}
{{{v - v1 = 400 mph}}}.......add and solve for {{{v}}}

{{{2v = 880mph}}}

{{{v = 440 mph}}} .....the speed of the plane in still air