07-13-2017, 04:59 AM
Voted
A group of 13 people are locked in a room by an evil genie. To leave the room, everyone must shake hands with every other person once. Sadly, everyone is really slow at shaking hands, and it takes a pair of people 1 minute to shake hands (two separate pairs can shake hands at the same time, but everyone's left hand is dysfunctional so no one can shake hands with two people at once). What's the minimum amount of time it would take for everyone to leave the room?
[spoiler]13.
Each minute, 12 of the people are able to shake one hand (6 pairs) while the last person has no partner and has to wait for the next minute. If everyone shakes a new hand each time, they'll spend 12 minutes shaking hands and 1 minute waiting. Hence 13 minutes total.[/spoiler]
A group of 13 people are locked in a room by an evil genie. To leave the room, everyone must shake hands with every other person once. Sadly, everyone is really slow at shaking hands, and it takes a pair of people 1 minute to shake hands (two separate pairs can shake hands at the same time, but everyone's left hand is dysfunctional so no one can shake hands with two people at once). What's the minimum amount of time it would take for everyone to leave the room?
[spoiler]13.
Each minute, 12 of the people are able to shake one hand (6 pairs) while the last person has no partner and has to wait for the next minute. If everyone shakes a new hand each time, they'll spend 12 minutes shaking hands and 1 minute waiting. Hence 13 minutes total.[/spoiler]