GeekDad Puzzle of the Week: Costa Concordia Conundrum

Reading Time: 2 minutes

For a year after college I worked as a cruise ship musician, playing saxophone, flute and clarinet for Carnival and Royal Caribbean cruise lines. And I remember those first couple months, bunking below the water line in a room so small its bathroom allowed you to sit on the throne while taking a shower, thinking that every creak and heave was an iceberg or rocky outcrop slicing through the double hull. What would I do if the ship went down? Even now, every time I hear In the Mood I feel like I’m about to die.

Well, one thing we like to do here at GeekDad is to equip fathers with the skills we need to keep our families safe in crises like zombie uprising, super-volcano eruption, alien invasion…or sinking cruise liner. And in that spirit, here is this week’s puzzle:

You’re on an Italian cruise liner piloted by a cowardly megalomaniac when it slams into a reef and goes down, trapping you below the waterline with 99 other passengers. Each person uses 23 liters of pure oxygen per hour and the room starts with 250,000 liters of air at 20% oxygen. Each hour, you have a 5% chance of being rescued. Each person who tries to swim for safety has a 1% chance of reaching the surface and alerting help, thus immediately saving the remaining trapped passengers. When the room runs out of oxygen, everyone remaining dies instantly.

What strategy offers the best chance of the most survival survivors? (Hint: be very careful with probability — after two hours you DON’T have a 10% chance of being rescued, nor do you have a 100% chance of being rescued after 20 hours…)

Submit your answer to Geekdad Puzzle Central by Friday for your chance at a $50 ThinkGeek gift certificate! MTFBWU.

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