The casino in my neighbourhood is offering a new sidebet for blackjack. When I asked the pitboss what the house percentage was for this bet he made some comments like "not much" and "in the real game it's always different". In other words, he wouldn't tell me.
The rules are the following: before any cards are dealt, you can wager 5 guilders on the hand of the dealer. If the dealer gets a blackjack in spades, you're paid 100 times that bet. If the dealer gets a blackjack in diamonds, hearts or clubs, you get paid ten times. When the dealer gets a blackjack in mixed suits, you get paid 5 times and when the dealer busts, nothing happens with the side bet. In all other cases, you lose the side bet.
My calculations are as follows:
-The chance of the dealer getting a suited blackjack in spades is about 0.003.
-The chance of the dealer getting a suited blackjack in another suit is about 0.009.
-The chance of the dealer getting a non-suited blackjack is about 0.036
-The chance of the dealer busting is about 0.28 (I'm not sure if this is correct, I used the busting percentages given a certain upcard from The Theory of Black Jack).
-The chance that you lose your sidebet is about 0.67.
All this gives you an expected value of -1,43 guilder on your 5 guilder bet. Which means the house has about a 28.5% advantage on this bet. No wonder the pitboss wouldn't tell me.
Please let me know if my calculations are correct and if not what they should be.
Thanks,
Peter Woerde
PS: It's a six deck game and unfortunately counting isn't possible (CSM's).
