For an outdoor event organizers, the expected number of people who will attend is 32700
SOLUTION:
Given, For an outdoor event organizers estimate that 60000 people will attend if it is not raining.
And If it is raining, event organizers estimate that 21000 people will attend.
On the day of the show, meteorologists predicted a 70% chance of rain.
We have to determine the expected number of people who will attend.
Now, number of people = 70% of rain case + 30% of other case.
Number of people = 0.7 x rain case + 0.3 x other case
Number of people = 0.7 x 21000 + 0.3 x 60000
= 2100 x 7 + 6000 x 3 = 32700.
Hence, the expected count is 32700