Question 1011742
Travel rates rule, RT=D relates rate R, time T, distance D.

<pre>
Y    speed in still air
X    wind speed
430  with wind
270  against wind
</pre>

{{{system(Y+X=430,Y-X=270)}}}


{{{system(Y=430-X,Y=270+X)}}}


{{{system(Y=430-X,Y-270=X)}}}


{{{Y=430-(Y-270)}}}


{{{Y=430-Y+270}}}
{{{2Y=700}}}
{{{highlight(Y=350)}}}-----the speed of the vehicle in still air