+1000 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?
+1950 Let's find how far everyone ran when Dirk finished.
When Dirk finishes, Edith has ran 14km while Foley has only ran 9km.
This means that Foley runs only 9/14 as fast as Edith.
We can now find how far Foley ran when Edith finished the race.
Plugging in 24, we find that Foley has only ran 24(9/14)≈15.43km when Edith ran 24.
This means Foley was 24−15.43≈8.57km behind Edith.
So our final answer is 8.57km.
Thanks! :)
