The minimum number of crossings required for the boat to get all four people across the river can be achieved as follows:
1. First, the two lightest people, weighing a total of 80 pounds, cross together. This is the first crossing.
2. One of the two lightest people, weighing 80 pounds, goes back alone. This is the second crossing.
3. The two heaviest people, weighing a total of 370 pounds, cross together. This is the third crossing.
4. One of the two heaviest people, weighing 190 pounds, goes back alone. This is the fourth crossing.
5. The two lightest people, weighing a total of 200 pounds, cross together. This is the fifth crossing.
Therefore, the minimum number of crossings required for the boat to get all four people across the river is 5 crossings.
four people want to cross the river. there is only one boat available and it can carry and maximum of 200 pounds. the weights of four people are 190, 180, 120, and 80 pounds. each tune the boat crosses the river from on shore to the other is counted as one crossing of the boat. what is the minimum number of crossings required for the boat
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