
Here is a solution to the Bridge and
Flashlight problem. Recall the labeling as
A = 1 minute
B = 2 minutes
C = 5 minutes
D = 6 minutes
1) A and B cross.
2 minutes pass, 2 minutes total
Side 1: C, D
Side 2: A, B
2) B crosses back (please see Note).
2 minutes pass, 4 minutes total
Side 1: B, C, D
Side 2: A
3) C and D cross.
6 minutes pass, 10 minutes total
Side 1: B
Side 2: A, C, D
4) A crosses back.
1 minutes passes, 11 minutes total
Side 1: A, B
Side 2: C, D
5) A and B cross.
2 minutes pass, 13 minutes total
Side 1: Nobody
Side 2: A, B, C, D
Note) In step (2) A could have crossed back leaving B behind. It may
seem like that would save another minute. However, in step (4) where A
would have crossed back, he's not there anymore. But B is, so now we
would have the same total minutes again. Just a small variation of
this soln.
Thank you :) 


To solve this puzzle first you have
to have a left and right side of the bridge. All four people are on
the right side of the bridge.
The first to cross to the left side of the bridge are the 1 and 2
minute persons. This leaves 11 minutes.
The 2 minute person stays on the left side while the 1 minute person
goes to the right side with the flashlight, leaving 10 minutes.
The 1 minute person stays on the right side while the 5 and 6 minute
person goes to the left side, leaving 4 minutes.
Now the 2, 5 and 6 minute person are on the left and the 1 minute
person on the right. The 2 minute person goes back over the bridge
with the flashlight, leaving 2 minutes.
Now, the 5 and 6 minute persons are on the left and the 1 and 2 minute
persons are on the right. Finally, the 1 and 2 minute persons cross to
the left side of the bridge leaving 0 minutes left and all people on
the left side.
Good Luck 
