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[jack_chay]

Its digging my head in... i keep getting a negative... HELP !!!

Alfred and Bertie play a game, each starting with $100. Two dice are thrown. If the total
score is 5 or more then Alfred pays $x, where 0 < x ≤ 8, to Bertie. If the total score is 4 or
less then Bertie pays $(x + to Alfred.

Given that x = 3, find the variance of Alfred’s cash after the first game.

Thanks in advance

[09Ti08]

Alfred's cash:
- if the sum > or = 5: pr(sum > or = 5) = 30/36, then X=100-3=$97
- otherwise: pr(sum < 5) = 6/36, then X=100+3+8=$111
Hopefully you realize that I'm talking about a probability distribution function.
Now E(X)=97*30/36+111*6/36=99.33