Answer:
410
Explanation:
20 rows of 12 means there are x amount of people in the 20 rows of 12 seats.
x=20*12
x=240
20 rows of 10 means there are y amount of people in the 20 rows of 10 seats.
y=20*10
y=200
We know that there are 440 seats in the theater. (240+200)
Since 30 chairs are not full, we subtract 440 from 30 and you get 410.
There are 410 people in the theater.