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X and Y departed from a town together for another town 45 km away. If the speed of X is 1 km/h more than that of Y, he reaches his destination half an hour earlier than Y. Find the speed of X and Y.

 Jun 27, 2020
 #1
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rate x time = d

 

rates    x   and x+1       time     t1   and  t1-1/2        (1/2 hr = 30 minutes)

x(t1) = 45   or    t1 = 45/x

and

  (x+1)(t1-1/2) = 45

   (x+1)(45/x-1/2) = 45

    45 -1/2x + 45/x-1/2 = 45

     -1/2x + 45/x -1/2 = 0

-1/2x^2 -1/2x +45 = 0                 x = 9 km/hr from Quadratic formula    then t1 = 45/9 =5 hr     x+1 = 10 km/hr

 Jun 28, 2020

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