Three Hikers and a 100 kg Boat Limit

Yes, it is possible

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The hikers can proceed as follows:

1. The 45 kg and 50 kg hikers cross the river together.
2. The 45 kg hiker returns with the boat.
3. The 80 kg hiker crosses the river alone.
4. The 50 kg hiker takes the boat back.
5. Finally, the 45 kg and 50 kg hikers cross the river together once more.

All three hikers successfully cross the river using this strategy while respecting the boat's 100 kg weight limit.

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