Question 1199900
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Buduli covers a distance of 8 km to his house in 1 hour.He walks part of 
the distance at 6 km/h and runs the rest at 10 km/h. How many kilometers did he run.
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<pre>
Let d be the distance he ran, in kilometers.

Then the distance he walked was (8-d) kilometers.


Write the time equation

    {{{d/10}}} + {{{(8-d)/6}}} = 1  hour.


To solve it, multiply both sides of equation by 30.  You will get

    3d + 5*(8-d) = 30.


Simplify and find d

    3d + 40 - 5d = 30

    40 - 30 = 5d - 3d

      10    =   2d

       d    =    10/2 = 5.


<U>ANSWER</U>.  Buduli ran 5 kilometers.


<U>CHECK</U>.   {{{5/10}}} + {{{(8-5)/6}}} = {{{5/10}}} + {{{3/6}}} = {{{1/2}}} + {{{1/2}}} = 1 hour, the total time.   ! correct !
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Solved.