Answer
$P(E)=0.6$
Work Step by Step
The events "red", "blue" and "yellow" are disjoint (mutually exclusive).
$N(S)=5$
$N(red)=1$
$N(blue)=1$
$N(yellow)=1$
Using the Addition Rule for Disjoint Events (page 270):
$P(E)=P(red~or~blue~or~yellow)=P(red)+P(blue)+P(yellow)=\frac{N(red)}{N(S)}+\frac{N(blue)}{N(S)}+\frac{N(yellow)}{N(S)}=\frac{1}{5}+\frac{1}{5}+\frac{1}{5}=\frac{3}{5}=0.6$
