2. Four persons can cross a bridge in 3,7,13,17 minutes. Only two can cross at a time. find the
minimum time taken by the four to cross the bridge.
ans:20
1)Send the 17 and the 13.Originally Posted by bharathlece
2)After 13 min, 13-guy finished and 17-guy walked for 13 min, there is room for another.
3)Now send the 7 minute guy.
4)After 4 min, the 17-guy finished and 7-guy waled for 4 min, there is room for another.
5)Send the 3 minute guy.
6)After 3 minutes both the 3 and 4 guys finished on time.
In total 20 minutes where used.