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?

magenta Dec 16, 2023

#1**+1 **

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

CPhill Dec 16, 2023