I will assume that a player gets to reach in the barrel and blindly select 1 bill that he is allowed to keep. There are 20+10+5+3+1+1 = 40 bills Value Probability Expectation of of = Value × Bill drawing Probability -------------------------------------------- $1 20/40 = 1/2 $1×(1/2) = $0.50 $2 10/40 = 1/4 $2×(1/4) = $0.50 $5 5/40 = 1/8 $5×(1/8) = $0.625 $10 3/40 $10×(3/40) = $0.75 $20 1/40 $20×(1/40) = $0.50 $100 1/40 $100×(1/40) = $2.50 -------------------------------------------- Totals 40/40 = 1 $5.375 If a player plays the game many times, she/he will average walking away with $5.375 each time. So to make the game profitable to those in charge, they should charge more than $5.375 to play. [For instance if they charge $10 to play, they will average profiting $10.00 - $5.375 or $4.625 each time someone plays.] Edwin