Geometric probability · Coffee shop · difficulty 4 of 5
All three at once
Three friends each arrive at a coffee shop at an independent, uniformly random time between 1:00 and 2:00 pm. Each stays exactly 20 minutes and then leaves, even if that runs past 2:00. What is the probability that at some moment all three are in the coffee shop together?
Answer with a probability. First lock in a gut guess with an 80% range, then solve it properly, then watch a simulation settle on the truth.
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