Question 879186
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Hi
Using total time for the trip in the Set Up
{{{90mi/r + 90mi/(r/2) = 8/2}}}
{{{90/r + 180/r = 8/2}}}  |Multiplying thru by 2r so as all denominators = 1
    180 + 360 = 8r
         67.5mph = r
67.5mph and 38.75mph