Question

determine the number of people who participated in weight - training (w) and cardio (c).

Explanation:

Step1: Understand the Venn - diagram concept

In a Venn diagram for two sets \(W\) (weight - training) and \(C\) (cardio), the intersection of the two sets represents the number of people who participated in both activities.

Step2: Identify the intersection value

Looking at the given Venn - diagram, the number in the overlapping region (intersection) of the two circles (representing \(W\) and \(C\)) is \(15\).

Answer:

\(15\)