You are in the army. You are standing at a gorge which is crossed by a rope bridge. It is pitch black and you only have one torch. You know the bridge is going to blow up in 17 mins and you have to get your 3 men and yourself across the bridge in 17 mins before the bridge blows.
You take 1min to cross the bridge.
X takes 2 mins to cross
Y is overweight and takes 5 mins to cross
Z is injured and takes 10 mins to cross.
The rope bridge can only support the weight of two men at any one time. One of you must always return with the torch as it is impossible to cross the bridge if you can’t see. Whoever crosses always takes the time of the slowest persons as you have to help them.
How do you save all you team and do it??