I have got an interesting riddle for those that are interested.
Picture yourself a group of 4 people out in the bush.
In the middle of the night they reach a crappy looking rope bridge from which they expect only 2 persons max. can walk across at the same time.
Only it is so dark that they cannot even see the other side of the canyon they want to cross.
1. The party has only 1 flashlight from which the battery only has 17 minutes left and crossing the bridge without the flashlight is impossible.
2. Only 2 people max are allowed to walk across the bridge at the same time.
3. Considering that crossing the bridge without a flashlight is not possible 1 who has already crossed the bridge must return to meet with the other members left behind.
4. Both crossing persons walk the speed of the slowest.
5. All 4 people vary in walking speed.
Person no.1 is expected to reach the opposite side in 1 minute.
Person no.2 is expected to reach the opposite side in 2 minutes.
Person no.3 is expected to reach the opposite side in 5 minutes.
Person no.4 is expected to reach the opposite side in 10 minutes.
Who can tell me the combination in which the 4 persons have to walk back and forth in order for all to reach the other side before the battery of the flashlight is empty. (2 persons forth, 1 back)
Have fun