Question 670129
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Hi,
 180-mile trip 
 If you were to increase your speed{{{highlight(x)}}} by 5 miles per hour the trip would take 24 minutes less than usual
 t = 180/x
t - .4 = 180/(x+5)
180/x - .4 = 180/(x+5)
180(x+5) - .5x(x+5) = 180x
      900 = .5x^2 + 2.5x
          5x^2 + 25x -9000 = 0
           x^2 + 5x - 1800 = 0
      ( x -40)(x + 45) = 0 , x = 40mph   (throwing out negative solution for unit measure