Probability

#1
Hello! I will appreciate if anyone can help me with this problem. Thank you!:)

40% of vacationers going to rocky mt. region visit yellowstone park, 30% visit Tetons, 20% percent visit both. What is the probability that the vacationer visits yellowstone park or tetons?'
 

BGM

TS Contributor
#3
As Outlier suggested you may use Venn's Diagram to help you to visualize the set relations. You may also use inclusion-exclusion principle to help.