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: Fastest solution yet? correct? by Hugo)

No, I am still at 26 minutes, unless I am missing something. 

A&B take 10 minutes across bridge 1, but c,d,&e begin there 16 minute sequence (across both bridges, with the second flashlight) at time 10 min. 10+16=26. 

The first ten minutes of c,d,&e,'s cross sequence is simultaneous with the second ten minutes of a&b crossing bridge two (with the first flashlight).

Again, unless I am missing something I believe you added my time wrong.

Edited on June 27, 2005, 8:14 pm

Posted by john on 2005-06-27 20:13:45