In the puzzle Four people on a Bridge we met four people who needed to cross a bridge at night. In this puzzle, there are five people who must cross two sequential bridges at night. As in the original puzzle, there are some hindrances:

The bridges can only support two people crossing at a time.

Each person has a different speed in which they can cross: 10 minutes, 7 minutes, 5 minutes, 2 minutes, and 1 minute.

They have only two flashlights to share among them.

What is the shortest amount of time it will take for all five people to cross both bridges?

(In reply to re: solution by Awdreye)

a-10min b-7min c-5min d-2min e-1min

First time cross-
bridge 1- a&b cross (a-b=2min) -b=a&d cross
at same time bridge 2- c&e (c-e=4 min) (a-c=5 min)
if a&b left at same time as c&e/e gets across first/c gets across second leavin 5 min for a to still get across/b gets across third leavin a 2 min still to cross/d and a get across same time because with the 2 min a still needed to get across when b got off the bridge d could get on and within the 2 min d needs to get across both a and d would get across at the same time/meaning all 5 people can get across in 10 min/then so each person gets across on both bridges meaning all have used both bridges they can switch bridges using the same method/takes a total of 20 min for each person to cross both bridges/because it never said they couldnt use both bridges at the same time I think my method is the quickest and each person crosses both bridges.

sorry for all the posts...but I dont know how to edit my posts...so sorry for that...but I hope you look at my method and give it some thought and let me know if my method would work...if you could email your thoughts to me...I dont know how long it will take for me to see if you wrote anything to me.../email: lovinxhimxhurtz@aol.com .../thanks ~*Awdreye*~

Posted by Awdreye on 2005-06-28 07:50:51