J :6. Solution. On each roll of the wheel, you win ten dollars if the ball falls in one of the 18 slots marked red and you lose ten dollars - or "win" -10 dollars if the ball falls in one of the 18 slots marked black or one of the 2 slots marked green. The amount won on a single bet is like one draw out of a box with 18 tickets marked 10, and 20 tickets marked -10. In 100 spins, your total winnings are like the sum of 100 draws from this box.