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?

LiIIiam0216 Mar 3, 2024

#1**+1 **

When Edith finishes the race, how far behind is Foley, in km?

**Hello Lilliam0216!**

\(v_d=24km/t_d\\ v_e=(24-5)km/t_d=19km/t_d\\ v_f=(24-6)km/t_d=18km/t_d\\ t_e=\frac{24km}{v_e}=\frac{24km\cdot t_d}{19km}\\ s_f=v_f\cdot t_e=\frac{18km}{t_d}\cdot \frac{24km\cdot t_d}{19km}=22.737km\)

Foley was (24-22.737)km=1.263km behind when Edith finished the race.

!

asinus Mar 5, 2024