<PRE><B>Question 184155</B>
240/(420-w)+240/(420+w)=70/60
[240(420-w)+240(420+w)]/(420+w)(420-w)=70/60
(100,800-240w+100,800+240w/(176,400-w^2)=70/60
201,600/(176,400-w^2)=70/60
60*201,600=70(176,400-70w^2)
12,096,000=12,348,000-70w^2
70w^2=-12,096,000+12,348,000=0
70w^2=252,000
w^2=252,000/70
w^2=3600
w=sqrt3600
w=60 mph. for the wind.
Proof:
240/(420-60)+240/(420+60)=70/60
240/360+240/480=70/60
2/3+1/2=7/6
7/6=7/6




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