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?
So, first let's analyze the question.
Note that when Dirk finishes, Edith has ran 14km and Foley has run 9km.
Well, this means Foley runs \(9/14\) as fast as Edith.
So when Edith runs the entire 24km, Foley has ran \(24 (9/14) ≈ 15.43 km\)
Which means that Foley is \(24 - 15.43 ≈ 8.57 km \) behind Edith.
So 8.57 km is our answer!
Thanks! :)