Answer
P(heart or club or diamond) $=\frac{3}{4}=0.75$
Work Step by Step
The sample space S = "a standard 52-card deck". So, N(S) = 52.
Let E be the event "a club card". So, as shown in Figure 9, N(E) = 13.
Let F be the event "a heart card". So, as shown in Figure 9, N(F) = 13.
Let G be the event "a diamond card". So, as shown in Figure 9, N(G) = 13
The events "a heart card", "a club card" and "a diamond card" are mutually exclusive. So:
P(heart or club or diamond) = P(heart) + P(club) + P(diamond) =
$\frac{N(heart)}{N(S)}+\frac{N(club)}{N(S)}+\frac{N(diamond)}{N(S)}=\frac{13}{52}+\frac{13}{52}+\frac{13}{52}=\frac{39}{52}=\frac{3}{4}=0.75$
