21/02/26 22:05:22.09 YeaYmsBM.net
sim <- function(n,white=5,black=5){
pick <- function(x,one=1){
i=sample(length(x),one)
picked=x[i]
rest=x[-i]
list(picked=picked,rest=rest)
}
ball=list(picked=NULL,rest=rep(1:0,c(white,black)))
n_rest=length(ball$rest)
score=0
counter=0
while(counter < n){
status=pick(ball$rest,1)
score = score + (if(status$picked==1) 1 else rbinom(1,1,2/6))
ball$rest=status$rest
counter=counter+1
}
score
}
# n=2 score=2
MASS::fractions(20/90*1/3*1/3 + 50/90*1/3 + 20/90) ; 35/81
mean(replicate(1e5,sim(2)==2))
# n=4 score>=2
mean(replicate(1e6,sim(4)>=2))