A roulett wheel has 38 slots in which a ball can land two of e slots are green, 18 are red, 18 are black. The ball is equally likely to land in any slot, and each spin of the wheel is assumed to be independent.

Question

A)if the wheel is spun twice what is the probability that the ball lands on red and green in any order

B)if the wheel is spun twice calculate the probability that it lands on black at least once.

Answer 1

18/38 times 2/38

Black at least once is the opposite of never black..

20/38 times 20/38 subtract this answer from 1 to get at least once for black.