EXAMPLE 1.6.12 SOLUTION

The information refers to two overlapping categories: "wears dark glasses" and "smokes cigars." We can organize the information in the following two-circle Venn diagram:

1. To answer the question "How many wear dark glasses and don't smoke cigars?" we recognize that the diagram shows 2 people who are within the set "wear dark glasses" yet are outside of the set "smoke cigars," so the answer is 2.

2. To answer the question "How many wear dark glasses or smoke cigars" we add all the numbers in those two circles: 2 + 28 + 4 = 34