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Marlene rides her bicycle to her friend​ jon's house and returns home by the same route. marlene rides her bike at constant speeds of 9 mph on level​ ground, 6 mph when going uphill and 18 mph when going downhill. if her total time riding was 1 ​hours, how far is it to​ jon's house?

Respuesta :

shinmin

To solve the problem:

Let f = distance one way distance on level ground


Let h = distance rode on the hill


Write a time equation; where Time = distance/speed:



level time + uphill time + downhill time + level time = 1hr


f/9 + h/6 + h/18 + f/9 = 1 hr



Multiply equation by 18 to get rid of the denominators


 

2f + 3h + h + 2f = 18


4f + 4h = 18


Simplify by dividing this by 4


f + h = 4.5 miles is took her to get to Jon’s house.

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