Question 1145150
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First find the time for the 18-years old runner. 

It is   {{{T[1]}}} = {{{10000/4.74}}}  seconds.



Next find the time for the 50-years old runner.  

It is  {{{T[2]}}} = {{{10000/4.17}}}  seconds.



The difference {{{T[2]}}} - {{{T[1]}}} will be your answer, in seconds.
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