38. Family River Crossing with a 60 kg Boat Limit Rajan (60 kg), his wife (40 kg) and their son (20 kg) need to cross a river in a small rowing boat. There is no boatman: anyone in the boat must do the rowing.The boat can carry at most 60 kg at a time.How can all three family members reach the opposite bank without exceeding the weight limit at any point? Added 24 January 2012 Show Hint Show Solution Hint: Notice that the wife and son together weigh exactly the boat's limit. Use them as the regular ferry crew so the boat can keep coming back for Rajan. Solution: Label the starting bank A and the far bank B. Each numbered line shows who is in the boat and the direction of travel.Wife + Son (40 + 20 = 60 kg) row from A to B.Son (20 kg) rows back from B to A, leaving the wife on bank B.Rajan (60 kg) rows alone from A to B.Wife (40 kg) rows back from B to A, joining the son.Wife + Son (60 kg) row together from A to B.All three—Rajan, his wife, and their son—are now safely on bank B, and the weight limit was never exceeded.
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