Srt the RATES equal and solve for 'x'
 
(x+5) / (x-1) = (x+11)/(x+2)       solve for 'x' (if possible )     Start by cross multiplying, simplify then use Quadratic FOrmula
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Then   speed in MPH  = (x+5)/(x-1)     or     (x+11)/(x+2)       <===== they should be the same for the Q