Answer
$P(Peanut~Butter~Patties®/Tagalongs™~or~Peanut~Butter~Sandwich/Do-si-dos™)=0.24$
Work Step by Step
The events "Peanut Butter Patties®/Tagalongs™" and "Peanut Butter Sandwich/Do-si-dos™" are mutually exclusives (disjoint events).
Using the Addition Rule for Disjoint Events (page 270):
$P(Peanut~Butter~Patties®/Tagalongs™~or~Peanut~Butter~Sandwich/Do-si-dos™)=P(Peanut~Butter~Patties®/Tagalongs™)+P(Peanut~Butter~Sandwich/Do-si-dos™)=0.13+0.11=0.24$
