for jinjing - 鸭子落湖中...

鸭子落到圆形湖中，狐狸在岸边想吃鸭子。鸭子受伤，无法从水里起飞，必须游到岸边才能起飞。狐狸在岸上跑的速度是鸭子速度的4.60338811倍 (or 鸭子速度= 0.21723363倍狐狸) 倍，问鸭子是否可以游到岸边起飞跑掉？how?

思路已经讨论过了， 答案下边贴了，I did not explain the word-by-word and step-by-step solutions. Just see if anyone can clarify this for Jinjing.