KöMaL 2023 B5344

Anti and Bandi would like to get from Balatonmáriafürdő to Balatonlelle, which is 30 kilometers away, partly on foot and partly by bicycle. They start at the same time, and they only have a single bicycle. Anti's speed by bicycle is 30 km/h, and he can run with a speed of 15 km/h. Bandi's speed by bicycle is 20 km/h, and he can run with a speed of 12 km/h. Find the least amount of time they need to get to their destination in minutes. (During their trip they can swap the bicycle with each other as many times as they want, and the bicycle can be safely left at the side of the road.)