The width of a river is 300 m, the velocity of the river is 3 M / s, and the speed of the boat in still water is 4 m / s The width of a river is 300 m, the velocity of the river is 3 M / s, and the speed of a small boat in still water is 4 m / s?

cosa=v1/v2=3/4=0.75
The angle between the upstream and the river bank is a, and the boat can reach the opposite bank
a=41.4°
Or arccos 0.75

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