2015 UMO Problems/Problem 4


Anastasia and Balthazar need to go to the grocery store, which is $100$ km away. Anastasia walks at $5$ km/hr, and Balthazar walks at $4$ km/hr. However, they also own a single bike, and each of them bikes at $10$ km/hr. They are allowed to go forwards or backwards, and the bike will not get stolen if they drop it off along the way for the other person to pick up. What is the shortest amount of time necessary for both of them to get to the grocery store?


See Also

2015 UMO (ProblemsAnswer KeyResources)
Preceded by
Problem 3
Followed by
Problem 5
1 2 3 4 5 6
All UMO Problems and Solutions
Invalid username
Login to AoPS