This is a tough problem.....?

Question

There are four people on a bridge at night. It is PITCH BLACK nothing can be seen without a flash light. The four people are on the bridge with only ONE flash light. All four of these people must cross this bridge and end up on the other side together. When crossing the flashlight must be taken across and be brought ALL THE WAY back to be used again. The bridge only allows for 2 people to cross at a time. These four people all get across at a different rate of time. The first person takes ONE MINUTE to get across, the second person takes TWO MINUTES to get across, and the third person takes FIVE MINUTES to get across, and the fourth person takes TEN MINUTES to get across. The two people that are crossing must cross at the SLOWER persons pace (ex. If one and ten crossed, it would take ten minutes, and some one would have to bring the flash light back). You must find a way in which all four of these people end up on the other side of the bridge TOGETHER, in less than 18 MINUTES!!!

Answer 1

Hmm...

First no. 1 and 2 cross = 2mins
Then 2 goes back = 2mins
Then 4 and 3 cross = 10mins
Then 1 goes back = 1min
Then 1 and 2 cross = 2mins

Total = 17 minutes, 1 minute to spare.

Answer 2

First, the third and fourth people cross together and the third returns (4 minutes consumed).

Second, the first and second people cross together and the fourth returns (11 minutes consumed).

Third, the third and fourth people cross together (2 minutes consumed).

Answer 3

1 min and 2 min cross = 2min
1 min returns = 1 min
5 min and 10 min cross= 10min
2 min returns = 2min
1 min and 2 min cross = 2
total = 17min