23。Five boxes maximum capacity currently hold pieces
90 70
80 70
50 30
80 50
40 40
rearrange it so that the maximum capacity - holding pieces for all five are the same. So second box should be ?
意思是重新调整各盒子的容纳数,使得所有盒子的最大容量减去实际容纳数相等。前4对都差20,第5差0 。所以差是20×0.8=16
80-16=64
[确认] 64
[思路] 所有差额的和为:20+10+20+30+0=80
5对数每对的平均差额为:80/5=16
second box:80-16=64
six cards with numbers 1,2,3,4,5,6 on them separately, are put in one bowl, pick out one card, put back and then pick out one card. If the sum of two cards are 8, what is the probabilities of card numbered with 5?
MY ANS:2/5