A traveler comes to a river with a 100 kg weight limit for the small raft. A father weighs 100 kg, and his two sons each weigh 50 kg. How can all three cross to the other side?
Both sons cross together. One son returns with the raft. The father crosses alone. The second son brings the raft back, and then both sons cross together.
1. Both sons (50kg + 50kg = 100kg) cross. 2. Son A returns (50kg). 3. Father crosses alone (100kg). 4. Son B returns (50kg). 5. Both sons cross again (100kg). All three are now across.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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