Question 24144
Let the speed of the plane be x 
Let the speed of the wind be y


1.7(x-y)=255 --->1.7x-1.7y=255 (equation 1)
1.5(x+y)=255 --->1.5x+1.5y=255 (equation 2)


Multiply equation 1 by 15 and equation 2 by 17 to get:
25.5x-25.5y=3825 (add)
25.5x+25.5y=4335  (add)
----------------
51x=8160 (divide both sides by 51)
x=160


Solve for y:
1.7(160)-1.7y=255
272-1.7y=255
-1.7y=--17
y=10


Hence the speed of the plane is 160mi/h and the speed of the wind is 10mi/h.
Paul.