Question 27
The distance between Coco da Selva and Quixajuba is $24~\mathrm{km}$. Two friends need to go from Quixajuba to Coco da Selva and a third friend needs to go from Coco da Selva to Quixajuba. They own a bicycle that is initially in Quixajuba. Each of them can walk at the speed of $6~\mathrm{km}/\mathrm{h}$, or by bicycle at the speed of $18~\mathrm{km}/\mathrm{h}$. In addition, they can leave the bike at any point on the route. 
Show how they can proceed to reach their destinations at maximum $2~\mathrm{h}~40~\mathrm{min}$.
Show how they can proceed to reach their destinations at maximum $2~\mathrm{h}~40~\mathrm{min}$.