Answer
$P(G~or~R)=\frac{10}{19}\approx0.526$
Work Step by Step
The sample space S = "38 slots". So, N(S) = 38.
Let R be the event "red slot" (odd-numbered). So, $N(R) = 18$.
Let B be the event "black slot" (even-numbered). So, $N(B) = 18$.
Let G be the event "0, 00" . So, $N(G)=2$.
Using the Addition Rule for Disjoint Events (Page 270):
$P(G~or~R) = P(G) + P(R) = \frac{N(G)}{N(S)}+\frac{N(R)}{N(S)}=\frac{2}{38}+\frac{18}{38}=\frac{20}{38}=\frac{10}{19}\approx0.526$
