# Getting Lapped

Alice and Carla are swimming in a pool when they decide to have a race. Carla is pretty fast and swims at a rate of 81m/min, while Alice only swims at a rate of 64m/min. Both girls swim down and back multiple times, and because Carla is faster than Alice, Carla laps Alice a few times during the race. If $$t$$ is the time it takes for Carla to lap Alice (in minutes) for the first time, what is the minimum length of the pool $$l$$ such that $$l$$ and $$t$$ are positive integers?

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