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 $5$ km behind, and Foley is $6$ km behind. When Edith finishes the race, how far behind is Foley, in km?
When Edith runs (24 - 5) miles =19 miles, Foley has run (24 - 6) = 18 miles
So.....Foley runs at (18/19) of Edith pace
When she finishes Foley has run (18/19) (24) = 432/19 km
So....he is 24 - 432 / 19 = 24/19 km behind
So basically the ratio between their speeds is 19 to 18, edith 19, so when edith finishes 19/19 of the race, foley finishes 18/19, meaning there is 1/19 left to go. 1/19 x 24 = 24/19