选择与除法 Choose and divide

题目描述

[problemUrl]: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=15&page=show_problem&problem=1316 [PDF](https://uva.onlinejudge.org/external/103/p10375.pdf) ![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10375/f4c82551d4d63248a3265b83e25132b66c043585.png)

输入输出格式

输入格式

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10375/8ff851cc9926c4165c7c6485311457578bf77f44.png)

输出格式

![](https://cdn.luogu.com.cn/upload/vjudge_pic/UVA10375/1dd11724e900842b1855cb026891122b11c4b9c5.png)

输入输出样例

输入样例 #1

10 5 14 9
93 45 84 59
145 95 143 92
995 487 996 488
2000 1000 1999 999
9998 4999 9996 4998

输出样例 #1

0.12587
505606.46055
1.28223
0.48996
2.00000
3.99960