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Three runners, Dirk, Edith, and Foley all start at the same time for a $24$ km race, and each of them runs at a constant speed. When Dirk finishes the race, Edith is $10$ km behind, and Foley is $15$ km behind.  When Edith finishes the race, how far behind is Foley, in km?

 Dec 16, 2023
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Edith runs 24 -10  = 14 km   when Dirk  has finished

And Foley is 5 m  behind Edith when Dirk finishes so he has run 9 m when Dirk finishes

So Foley's speed to  Edith's speed =  (9/14)E 

 

So  when  Edith finishes the race she has run 24 km   and  Foley has run  (24)(9/14)  ≈ 15.42 km

 

So....he is about    24 - 15.42  =  8.58 km behind

 

cool cool cool

 Dec 16, 2023

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