SOLUTION: Our teacher gave us a worded problem. But, it is like more of finding the area of the rectangle but different. I've been solving this problem for hours now and I don't know what st

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Our teacher gave us a worded problem. But, it is like more of finding the area of the rectangle but different. I've been solving this problem for hours now and I don't know what st      Log On


   

Question 981231: Our teacher gave us a worded problem. But, it is like more of finding the area of the rectangle but different. I've been solving this problem for hours now and I don't know what step I did wrong. Can you please help me find the roots, if it's factor-able or not, or the area? Thank you. OK here's the worded problem:
A rectangular park 80 meters long and 60 meters wide is surrounded by a driveway of uniform width. How wide is the driveway if its area is 3/25 of the area of the park?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
A diagram is often helpful. Try making one to represent the description.

w, width of the park
L, length of the park
u, the uniform width of the driveway around the park
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two given values: w=60, L=80
unknown value: u

Park area, wL
Total Area of park AND driveway, %28w%2B2u%29%28L%2B2u%29
Driveway area, %28w%2B2u%29%28L%2B2u%29-wL=%283%2F25%29wL

Solve the driveway area equation for u. It is quadratic in u. You can solve it completely in symbols before substituting the given values for evaluating u; or you can substitute the given values at any stage you want. There is some simplification you should do, BEFORE substituting the given w and L values.