Question 1127914
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Let D be the distance under the question, in kilometers.


Then your "time" equation is


{{{D/50}}} - {{{D/60}}} = 0.5    of an hour.


To solve the equation, multiply both sides by 300:


6D - 5D = 300*8.5


D = 150.


<U>Answer</U>.  The distance under the question is  150 kilometers.


<U>Check</U>.   The time to cover 150 km at 50 km/h  is   {{{150/50}}} = 3 hours.

          The time to cover 150 km at 60 km/h  is   {{{150/60}}} = 2.5 hours.

          The difference of times is  3 - 2.5 = 0.5  hours.   ! Correct !
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Solved.