宝くじをA,B併せて100本買ったときの賞金の期待値は

Award <- function(i){ #i:Aを買った本数
sum(dbinom(0:i,i,0.1)*(0:i)*100)+sum(dbinom(0:(100-i),100-i,0.01)*(0:(100-i))*1000)
}
sapply(0:100,Award)

> sapply(0:100,Award)
[1] 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000
....
[86] 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

と買い方に無関係にも思えるんだなぁ。