4 men must cross a bridge. A takes 1 min to cross. B takes 2 mins C takes 5 mins D takes 10 mins It is night time so they must carry a torch across. How do you get all them across, no more than two travelling at a time and done in 17mins? ----------------- A and b across- 2mins A back-1 minute C and D across- 10 mins B back-2 mins A and B across-2mins and that equals 17 mins