Question 28492
Let the speed of the wind be y
Let the speed of the plane be y



8x-8y=4240

second equation:
3(x+y)=2910
3x+3y=2910


Multiply the first equation by 3 and the second equatin by 8
24x-24y=12720
24x+24y=23280
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48x=36000
x=750


3(750)+3y=2910
3y=660
y=220


Hence, the speed of the jetstream is 220mph and the speed of the plane is 750mph.
Paul.