SOLUTION: An airplane traveling with a 20mph tailwind covers 270 miles. On the return trip against the wind, it covers 190 miles in the same amount of time. What is the speed of the plane?

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Question 855821: An airplane traveling with a 20mph tailwind covers 270 miles. On the return trip against the wind, it covers 190 miles in the same amount of time. What is the speed of the plane?
I set the equation like this : 270/x+20 = 190/x-20
I got an answer of 20 but my answer key says its 115 and I don't know how they arrived at that answer. Any help would be appreciated.
Thank you so much.
Melissa
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
Your equation yields an answer of x = 80/23=3.4783 for the plane and a time of 190/(20-80/23)=23/2 = 11.5 hours
I have no idea how you got 20 from your equation.
You have 270/x+20 = 190/x-20
x is the speed of the plane and 20 is the speed of the wind
Subtract the wind from the plane not the plane from the wind.
Your equation is set up wrong. It is close but not right.
270/(x+20) = 190/(x-20) which yields 115 for x the speed of the plane