Answer:

Explanation:
Given that at the race car rally attendees can sit in the bleachers the balcony or the grass.
In other words, there are only 3 options for the attendees and one person cannot sit in more than 1.
Hence sitting in bleachers, the balcony or the grass are three events which are mutually exclusive and exhaustive
This leads to the equation
Prob(sitting in bleachers)+Prob (sitting in balcony)+Prob (sitting in grass) =1
Let p be the probability for sitting in grass.
Substitute to get
