Crossing the Bridge Puzzle

 Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

Solution:     Total 17 min.

crossing the bridge puzzle

1 and 2 go first, then 1 comes back. Then 7 and 10 go and 2 comes back. Then 1 and 2 go again, it makes a total of 17 minutes.

1 & 2 Crosses Time –> 2Min
1 return Time –> 1Min
3 & 4 Crosses Time –> 10Min
2 return Time –> 2Min
1 & 2 Cross Time –> 2Min
Total Time –> 17Min

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