Question 388500
Rate*Time=Distance
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Let P be the plane speed, W the wind speed.
With the wind,
{{{(P+W)2=1200}}}
1.{{{P+W=600}}}
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Against the wind, 
{{{(P-W)2.5=1200}}}
2.{{{P-W=480}}}
Add the two equations,
{{{P+W+P-W=600+480}}}
{{{2P=1080}}}
{{{highlight(P=540)}}}mph
Then from eq. 1,
{{{540+W=600}}}
{{{highlight(W=60)}}}mph