for jinjing - 鴨子落湖中...

鴨子落到圓形湖中，狐狸在岸邊想吃鴨子。鴨子受傷，無法從水裏起飛，必須遊到岸邊才能起飛。狐狸在岸上跑的速度是鴨子速度的4.60338811倍 (or 鴨子速度= 0.21723363倍狐狸) 倍，問鴨子是否可以遊到岸邊起飛跑掉？how?

思路已經討論過了， 答案下邊貼了，I did not explain the word-by-word and step-by-step solutions. Just see if anyone can clarify this for Jinjing.