请问一道princeton上的数学题

summer095

DS：

问题是Ken在跳远比赛中on his fifth and final attempt跳了多远？

两个条件分别是：

1 Ken最后一跳超过前四跳平均值2.5 feet

2 Ken的最后一跳使得他跳远的平均值由22.5feet 变成23feet

我选了第五个选项，可答案是2就足够了

解答里还告诉我23*5-22.5*4=25就是Ken最后一跳的距离，这样说来岂不是第五跳就是最后一跳？

我以为the fifth attempt 和the final attempt是两次跳远，难道这是指同一次吗？

请高手解答，谢谢！

summer095

没人回答吗？是不是翻译得不太好，我把原题贴出来吧。

How far did Ken jump on his fifth and final attempt in the state long jump finals?

(1) On his final jump, Ken exceeded the average length of his first four jumps by 2.5 feet.

(2) Ken's final jump increased the length of his average (arithmetic mean) jump from 22.5 feet to 23 feet.