【数学】08/30起数学寂静原始稿（更新到166题）09/10-13:55

划着澡盆去火星

A photographer will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row. The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her. How many such arrangements of the 6 people are possible?

A5
B6
C9
D24
E36
数学寂静27题好像是这道gwd的原题。

划着澡盆去火星

划着澡盆去火星 发表于 2018-8-31 13:42
A photographer will arrange 6 people of 6 different heights for photograph by placing them in two ro ...

忘说了 我觉得答案是a 一共五种

天天2018

非常感谢各位构筑的解答！

乔伊jane

Yaaaaang 发表于 2018-8-31 11:20
15题错了，我应该是答案166。

请问一下哪里错了呢~

乔伊jane

总觉得17题以前见过啊。。。。。。有哪位太太能考古出来吗~

乔伊jane

啊 我找到了 https://forum.chasedream.com/for ... =%E6%B2%B9%E7%AE%B1

greatsmf

谢谢！

一只椰子鸭

酒酿圆子_粥 发表于 2018-8-31 00:11
谢楼主。
第六题
(M+1)*(M-1)/24 reminder is r, what is r 1) M cannot be divided by 2; 2)M cannot be  ...

感谢你呀
但我有个疑问  题目中有没有说m 大于 1 啊 如果M 等于1 不就都不满足了？

lxorvxe

28题答案错了吧，题目不是说两个点是对角线的end point，那么5是对角线不是边长，正方形的边长应该是10√2

lxorvxe

45题的答案也有点问题吧，问的是没有s的车，所有的车都有t画韦恩图整个s都在t内，没有s就直接1-（7/8）*（2/3）=5/12