Ella exercises regularly Her fitness log for the last 12 mon

Ella exercises regularly. Her fitness log for the last 12 months shows that she jogged 25% of the days, rode her bike 18% of the days, and did both on 12% of the days. What is the probability that Ella would do at least one of these two types of exercises on any given day?

Solution

Let

J = jogged
B = biked

Thus,

P(J U B) = P(J) + P(B) - P(B and J)

= 0.25 + 0.18 - 0.12

= 0.31 [ANSWER]