Answer:
There were total 2900 seats in the theater.
Explanation:
Given that:
Seats filled by students = 1247 seats
Vacant seats = 57%
Total percentage of seats = 100%
Percentage of seats filled by students = (100-57)%
Percentage of seats filled by students = 43%
Let,
x be the total number of seats.
43% of x = 1247

Dividing both sides by 0.43

Hence,
There were total 2900 seats in the theater.