math
posted by Sarah .
A roulette wheel has 18 red slots and 18 black slots numbered alternately with the numbers 1 through 36. Two green slots are numbered 0 and 00. The winning number is determined by the slot into which a single marble rolls. Players are not allowed to bet on green. The house wins all bets if 0 or 00 comes up. What are the odds against a black number winning? A). 10:9 B). 9:10 C). 1:1 D). 19:9

There are 18 black numbers among 36 plus 0 and 00. This means that there are 20 ways a black number will lose.
20 out of 38 = 10/19
Does you first choice have a typo?