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builucaz1000
2 năm trước
Hai bến sông A và B cùng nằm trên một bờ sông, cách nhau 18km. Cho biết vận tốc của canô đối với nước là 4,5m/s, vận tốc của dòng nước đối với bờ sông là 1,5m/s. Hỏi canô phải đi xuôi dòng từ A đến B rồi đi ngược dòng từ B về A mất bao nhiêu thời gian?
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