What I See: 4 Persons Problem - Answer

What I See: 4 Persons Problem
Answer...
- 1 sec & 2 sec go to the other end. - 2 sec
- 1 sec returns back - 1 sec
- 5 sec & 10 sec go to the other end - 10 sec
- 2 sec guy returns back - 2 sec
- 2 sec & 1 sec go - 2 sec

Total = 17 sec