All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Logic
Five People on Two Bridges (Posted on 2005-06-25) Difficulty: 2 of 5
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?

See The Solution Submitted by Erik O.    
Rating: 3.8000 (5 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution 10 minutes | Comment 34 of 41 |

keep in mind that there are two bridges...so lets use them both. i use the time it takes them to cross to represent them.

Bridge 1- 10 and 7 cross w/flashlight                   10 min 

Bridge 2- 5 and 1 cross  w/flashlight                   5 min

Bridge 2- 1 goes back w/ flashlight                     1 min

Bridge 2- 1 and 2 cross w/ flashlight                    2 min

now, if you add up the numbers for bridge 2, its 8 minutes. so 5,1, and 2 can all cross bridge 2 before  10 and 7 even get across bridge 1. so the minimum time it would take is 10 min.

 


  Posted by Lacey on 2005-07-05 19:19:29
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (12)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information