Jesse, Devin, Seth and Antonio have to walk through a long dark tunnel. They only have one torch between them so a maximum of two people can go through the tunnel at any one time. Each person takes a different amount of time to get through the tunnel and if two people walk together they must walk at the rate of the slowest.
Jesse takes 3 minutes, Devin takes 5 minutes, Seth takes 8 minutes, Antonio takes 10 minutes. What is the least amount of time for all four to walk through the tunnel? 
Notes: 
Example:
If Seth and Antonio walk through the tunnel together it will take 10
minutes, If Seth then walks the torch back through the tunnel a total of 18 minutes will have passed. Continue till all four are at the other end of the tunnel.
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Topics: Starter  Logic  Problem Solving  Puzzles
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Previous Day  This starter is for 8 February  Next Day
28 minutes:
Jesse and Devin walk through taking 5 minutes
Jesse walks back with the torch taking 3 minutes [8 minutes total]
Seth and Antonio walk through taking 10 minutes [18 minutes total]
Devin walks back with the torch taking 5 minutes [23 minutes total]
Jesse and Devin walk through taking 5 minutes [28 minutes total]
Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click the button above to regenerate another version of this starter with different numbers and names.
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Here a concise URL for a version of this page without the comments.
Transum.org/go/?Start=February8
Here is the URL which will take them to Tran Tunnels, a mathematical adventure.