Re: [計量] The 20 people at a party are divided ...
※ 引述《dragonegg (egg)》之銘言:
: ※ 引述《yauu (真無雙亂舞)》之銘言:
: : 1. 0<p<1
: : the greatest value of p(1-p) : 1/2
: : 2. The 20 people at a party are divided into n mutually exclusive
: : groups in such a way that the number of peopel in any group does not
: : exceed the number in any other group by more than 1.
: : the value of n if at least one of the groups consists of 3 people : 6
: : 謝謝!!
: 1. p(1-p) = p - p^2 = -(p-1/2)^2 + 1/4 , 所以有最大值的情況發生在p = 1/2 ,
: p(1-p) = 1/4,因此選B
: 2. 一個group裡有3個人,按照題意,其他group裡只能含3個人 or 4個人,因此
: 3個人的group有4個,4個人的group有2個,n為6,選C
: 請大家多多指教了。
有可能分成兩人三人 或是三人四人
2x+3y=20
(x,y)=(1,6)
3x+4y=20
(x,y)=(4,2)
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 61.224.56.23
推
10/22 02:56, , 1F
10/22 02:56, 1F
推
10/22 12:14, , 2F
10/22 12:14, 2F
→
10/22 22:34, , 3F
10/22 22:34, 3F
→
10/22 22:34, , 4F
10/22 22:34, 4F
討論串 (同標題文章)