65. Motorcycle with a sidecar. Atkins, Baldwin, and Clark decided to go on a trip. Their journey will be 52 km. Atkins has a motorcycle with a one-person sidecar. He needs to take one of his companions for some distance, drop him off to walk the rest of the way, return, pick up the other companion who started walking at the same time, and continue so that all three arrive at the destination at the same time. How can this be done?

The motorcycle's speed is 20 km/h, Baldwin can walk at a speed of 5 km/h, and Clark at 4 km/h. Of course, each one tries to move as quickly as possible and does not stop anywhere along the way.

The problem could be made more complex by introducing more passengers, but in our case, it is so simplified that even all distances are expressed in whole kilometers.
65. Atkins drives Clark 40 km and drops him off to walk the remaining 12 km. Then he returns and picks up Baldwin 16 km from the start and drives him to the end. The three of them spend 5 hours on the road. Another solution is for Atkins to first drive Baldwin 36 km and return for Clark, who by this time has walked 12 km. In both cases, the motorcycle has traveled 100 km, including 24 km without passengers.